Deworming experience from start to finish.

Discussion in 'Emergencies / Diseases / Injuries and Cures' started by tgooberbutt, Dec 31, 2012.

  1. tgooberbutt

    tgooberbutt Chirping

    Dec 24, 2012
    So... A few weeks back I freaked when I saw a couple of dead roundworms (I think) in a blop (and then another) of chicken poo. I did as much hasty research as possible and dosed my chickens' water with piperizine. Then I saw tiny white creepy crawlies in more chicken poo, scrambled to find answers, and ordered and dosed each chicken with Ivermectin pour-on. A few days later, still more creepy crawlies :(

    Then I found the Necropsy results, is not coryza or CRD--parasites are rampant!!! thread here on BYC. I read every post possible on multiple threads, then posted, a video of the creepy crawlies:

    Dawg53 was kind enough to diagnose tapeworm. :|

    I think he's right about the tapeworm segments. But I'm also convinced about the roundworms that I saw a few weeks back.
    In the meantime, I've ordered (and started to read) a copy of Gail Damerow's The Chicken Health Handbook, where she details how to conduct a fecal float at home.

    So now, with one microscope, a copy of William Foreyt's Veterinary Parasitology Reference Manual, and bottles of valbazen, and Safeguard on order, I'm determined to get to the bottom of this worm problem, and solve it start to finish. (PS - still cheaper than going to local vets....who are NOT versed with chickens.)

    I'm going to document the diagnosis and de-worming process with my chickens here. The one-chicken that for sure has the creepy-crawlies is also my favorite, Phineas. She's a Dominique, just over a year old. After a raccoon attack when she was a couple months old, she lost vision in her left eye, and has a off-center, crooked beak. She was never a particularly good layer...medium eggs about 2x/wk, with maybe a jelly egg here-or-there. And this past Thanksgiving, someone tried to steal her from my backyard (she likes to be held and does not run away from people). She's in good spirits, has a bright comb, very friendly disposition, and is still very active. If it wasn't for the creepy poop, I would not have thought anything was particularly wrong. She does seem a bit light/thin though. I'm hoping the thinness and inconsistent/poor laying has been the result of the worms?

    Any advice, thoughts or suggestions are welcomed. I want Phineas and all my chickens to get better :), and I want to leave a good reference guide for others who run into the same issue.

  2. tgooberbutt

    tgooberbutt Chirping

    Dec 24, 2012
    PS - I have changed the coop litter material to sand now, instead of hay. My chickens have never walked on sand before, and they seem freaked out by it. they now jump straight from the door to the ladders/roosts, and try not to walk on the sand at all. Is this normal?
  3. cowcreekgeek

    cowcreekgeek Songster

    Sep 14, 2012
    Hurricane, WV
    Hello, fellow reinventor of the wheel ... although I miss my finest microscope, I can no longer make good use of it, and the float test cannot absolutely rule out the presence of worms. So as to spare you a lot of time/trouble, I suggest makin' good use of the informations and clinical studies provided by others far more qualified than us (even though some folks on here get offended that I do ~'-)

    As you can see, the best choice when you've found tapeworms is to use products that list Albendazole as the active ingredient, as this treatment will eliminate all worms. When tapeworms are not an issue? I prefer Fenbendazole, as it's been proven safe all the way up to 1 gram per kilogram of body weight. Although the opinions as to dosage vary, again? I suggest you turn to the clinical studies/trials on efficacy, where the ideal dosages have been proven definitively:

    Albendazole: A single dose of 20 mg/kg of body weight, followed by a second dose 7-10 days later.*
    * addition efforts may be required in order to prevent reinfestation

    Fenbendazole: 20 mg/kg of body weight for three consecutive days.

    Note that, again, some folks ignore the importance of such in-depth study, choosing to rely instead on their own personal experience, or what somebody else has told 'em to do, but the goal should always be to eliminate the infestation(s) with minimal risk to the bird(s). And, that's exactly what these dosages have been well proven to do.

    :: editing, so as to provide additional information ::


    Treatment Alternatives

    1. Tramisol[​IMG] (Active ingredient: Levamisole hydrochloride) - Schering Plough.
    Soluble Drench Powder approved in sheep, cattle, and pigs. Withdrawal for cattle is 48 hrs
    pre-slaughter, 72 hrs pre-slaughter for sheep and 72 hrs for pigs. Levamisole will not settle out in
    medication lines. Chicken and turkey dose is 16 mg active levamisole per pound of body weight
    delivered by proportioner over 3-4 hours as a bolus for capillaria and cecal worms in pullets and
    hens. There is no effect on hatch, egg production, feed conversion, or body weight when used at 8
    and 16 mg/pound of body weight dose. However, in the chicken, at 36 mg/pound, water intake is
    reduced, at 288 mg/pound, diarrhea occurs, and at 900 mg/pound, 20% mortality occurred. Egg
    residue clearance time is not known. For roundworms in broilers/pullets, the dose is 8 mg of active
    levamisole per pound of body weight. This is given as a bolus over 3-4 hours. Tissue withdrawal
    times and egg withdrawal times must be extrapolated and extended for safety based on data from
    approved food animal clearances (3,4,5,6,7,8).

    2. Valbazen[​IMG] Oral Suspension (Active ingredient: Albendazole) - Pfizer Animal Health
    Albendazole has been reported to be effective in the treatment of capillaria, ascaridia, heterakis, and
    tape worms in chickens. It has been labeled only for cattle and sheep. There is no poultry data
    available. Settling in drinker lines has not been reported as has been seen with other anthelmentics in
    this class. Cattle require a 7 day withdrawal and sheep require a 7 day withdrawal pre-slaughter.
    There is no available data on tissue or egg clearance time in poultry. There have been no reported
    negative effects on the performance of broilers, pullets and hens. Valbazen is supplied in 500 ml,
    1 liter, and 5 liter bottles of an 11.36% suspension. In chickens, the reported dose is 10 mg/kg of body
    weight (personal communication).
    The cattle dose is 1 liter of Valbazen 11.36% Suspension per 500 lb as an oral bolus via dosing gun
    or dose syringe. (4.54 mg albendazole/lb, 10 mg/kg). Sheep dose is 1 liter of Valbazen 11.36%
    Suspension per 664 animals weighing 50 lbs each (3.4 albendazole/lb, 7.5 mg/kg).

    3. Synanthic[​IMG] Bovine Dewormer Suspension, (Active ingredient, 22.5%: Oxfendazole) -
    Fort Dodge Animal Health
    Synanthic is reported to be effective for capillaria, ascarids, and heterakis. Synanthic does have
    activity against cattle tape worms, however, there is no data whether it will work against poultry
    There is 225 mg oxfendazole per ml and it is supplied in a 500 ml bottle for cattle. The
    withdrawal time is 7 days for cattle. There is no tissue-clearance data available for poultry, nor any
    data available on side-effects in poultry. The cattle dose is 2.05 mg/pound of body weight
    (4.5 mg/kg B.W.). There is also a 9.06% suspension available in a 1 liter bottle (90.6 mg/ml of
    oxfendazole). Settling out in water lines without agitation can be a problem (personal

    4. Safe-guard (Active ingredient: 10% suspension, Fenbendazole) - Beef and dairy cattle,
    oral parasiticide - Hoechst-Roussel
    Effective against capillaria, round, and cecal worms in chickens (not approved in chickens). It is
    approved for turkeys as a feed additive, 20% premix type A and B, 16ppm (14.6 gm/ton complete
    feed for 6 consecutive days) for control of adult and larvae round worms and cecal worms.
    The cattle dose is 2.3 mg/pound BW (5 mg/kg BW) as an oral bolus. Beef cattle withdrawal is
    8 days following the last treatment. For dairy cattle, there is no milk withdrawal time. Safe-guard
    is supplied in 1 liter and 1 gallon bottles. There may be a problem with settling out in drinker lines
    without agitation (personal experience).

    5. Ivermectin (1% injectable for cattle)
    Since Ivermectin went off-patent, there are several manufacturers producing it. Ivermectin has been
    used orally via extra-label scripts to treat Northern Fowl Mite and capillaria infestations. Only mites
    that are on the birds are killed. The 1% injectable cattle formulation has been used as follows
    (personal communication):
    • 1 ml of 1% Ivermectin injectible + 1 ml. propylene glycol + 2 gal H2O, proportion at 1
    oz./gal D.W.
    • Administer 2 times, 10-14 days apart. There is a 30 day withdrawal (destroy commercial
    eggs for 30 days post-therapy.)

    Also, as to the efficacy of Albendazole at specifically 20 mg/kg, I offer the following summary* of study:

    In the spring of 2006, 60 naturally infected hens obtained from a broiler-breeder farm in northwest Arkansas were used in a controlled titration study to determine the anthelmintic efficacy of albendazole in the treatment of both nematode and cestode infections. Albendazole was used at the dose rates of 0.0, 5.0, 10.0, and 20.0 mg/kg of BW, with all treatments given individually as an oral suspension on d 0 (split doses) and with necropsies for parasite collection conducted on d 7. There were 15 birds per treatment group. Statistically significant (P < 0.05) reductions in worm burdens from control levels were seen at the 5.0 mg/kg dose level for adult and larval stages of Ascaridia galli, Heterakis gallinarum, and Capillaria obsignata. A significant (P < 0.05) reduction in the numbers of Raillietina cesticillus (scolexes) from control group levels was seen only at the 20.0 mg/kg rate of treatment. For albendazole given at the rates of 5.0, 10.0, and 20.0 mg/kg, respective anthelmintic efficacies based on geometric means were 87.7, 91.2, and 98.2% (A. galli larvae); 100.0, 100.0, and 100.0% (A. galli adults); 96.9, 95.7, and 98.9% (H. gallinarum larvae); 92.7, 95.4, and 94.9% (H. gallinarum adults); 90.3, 91.3, and 95.1% (C. obsignata larvae and adults combined); and 73.1, 73.1, and 96.2% (R. cesticillus). No adverse reactions to albendazole were observed in this study.

    * full study:
    Last edited: Dec 31, 2012
    1 person likes this.
  4. tgooberbutt

    tgooberbutt Chirping

    Dec 24, 2012
    Hi cowcreekgeek - thanks for the info! The Tucker & Yazwinski article will be something that I read tonight.

    Unfortunately (or fortunately), I'm not going to do a necropsy on my live birds, so the intestinal picts you posted can't really help. I'm not going to try to disprove the presence of worms as I saw creepy crawlies in the feces. I just need to confirm what kinda of (multiple?) creep-crawlies there are based on the eggs that might be find-able.

    I'm by no means a vet, and the last bio class I took was back in high school, more than a decade ago. But if college and grad school have taught me anything, it's how to read textbooks, conduct academic research, and follow instructions. If I can do this correctly when I know there are eggs present, then in the future, even if I don't see eggs, I'll be able to test and see if I need to preventitively de-worm.
  5. cowcreekgeek

    cowcreekgeek Songster

    Sep 14, 2012
    Hurricane, WV
    I'm sure your living birds wouldn't wish to have necropsy as a part of their diagnosis ~'-)

    There are many organic methods to reduce the numbers, and possibly prevent infestations, and I'm a big fan of natural alternatives ... there's some things I'll never used on this land, or within my birds, but when it comes to internal/external parasites? I give into what I believe to be the best choices for controlling/eliminating them (amprolium for coccidia, fenbendazole or albendazole for worms, and permethrin w/o a catalyst for lice/mites/etc. ~'-)

    Again? That's just my preferences, based upon the findings of fact when researching. I've never had to deal w/ tapeworms; you might even be better off to raise your flock on wire for a while, and over a place you can later slash/burn, so as to prevent them from reinfestation. But, for certain: Albendazole will eliminate any of the other worms your chickens may have, while you're treating them for the tapeworms.
  6. tgooberbutt

    tgooberbutt Chirping

    Dec 24, 2012
    Anyone have experience using Praziquantel to treat tapeworms in chickens? I'm looking into Praziquantel because:
    • Veterinary Parasitology (ISBN0813824192) lists two treatments:
    1. Niclosamide @ 50mg/kg and
    2. Praziquantel @ 6mg/kg, to be repeated in 10-14 days.

    • I found two clinical trials, specifically on chickens:
    1. Nurelhuda, Elowni, & Hassan (1989). Anthelmintic activity of praziquantel on Raillietina Tetragona in chickens, Parasitology Research. 75(8), 655-656.
    2. Rajendran & Nadakal (1988). The efficacy of Praziquantel (Drncit R) against Raillietina Tetragona in Domestic Fowl. 26, 253-260. : 3, 5, and 10mg/kg in tablet form...10mg was 100%, 5mg was 73%, 3mg was 46% effective. Male, female, age...all equally effective.

    Both of the empirical studies showed 100% elimination of tapeworms (Raillietina Tetragona) at 10mg/kg with no adverse effects on the chickens (though the chickens were slaughtered at 7, 14, and 20 days after treatment). And the treatment seem more effective as the infestation has gone on longer. That is to say, it's tougher to get rid of the immature worms, easier to get rid of the mature worms. The second study showed worm discharge as soon as 2hrs after medication.

    I'm thinking of the 10mg/kg with a followup on day 10 of the same (though the Rajendran & Nadakal article only gave one dose). And my followup to this is, Praziquantel seems to be sold in its pure form as a fish dewormer: Aqua-Prazi..... the ones made for cats and dogs seemed to me mixed with stuff. Thoughts?
  7. maggiemo

    maggiemo Songster

    Sep 1, 2012
    Front Range Colorado
    1 person likes this.

  8. cowcreekgeek

    cowcreekgeek Songster

    Sep 14, 2012
    Hurricane, WV
    :: edit ::
    This is true, as evidenced w/in other studies I've seen ...

    Praziquantel, at 21 mg or 34 mg, or a single custom dosage,
    for $1.50 + $1.99 shipping = $3.49 US.

    Praziquantel, in larger volumes, for $1 w/ flat $4 shipping, or
    (4 order x $1) + $4 shipping = 1,000 mg for $8 US.

    Gotta LOVE eBay ~'-)
    :: /edit ::

    Praziquantel @ 6mg/kg = UNDERDOSAGE, in my opinion.

    I had been suggesting Albendazole, at the rate of 20 mg/kg, as a single, and later repeated, dose.

    Considering the circumstance you're currently in, I'd bump it to 25 mg/kg, for three consecutive days, as per the results of the second study below. For certain, the safety of Albendazole is well proven well beyond these levels, and the fact that you can rid your birds of every type of worm they could possibly be infected w/ is a huge plus, in that you only have to purchase/use one active ingredient.

    Anticetodel Activity of Tapines, Praziquantel and Albendazole in Chickens
    Abstract of Study:

    ...levels of effectiveness of tapinex in single (400-1200 mg/kg) or multiple oral dosages (400 mg/kg/day), albendazole of 2.5 or 12.5 mg/kg/day and praziquantel at 300 mg/kg/day for 3 or 7 consecutive days against the tapeworm were estimated. High levels of anticestodal activity were obtained in chicks which had been dosed with praziquantel (100% efficacy) and tapinex (75-to 87.5% efficacy). Efficacy of albendazole against R. tetragona infection in chicks ranged from 37.14% (2.5 mg/kg/day) to 73.7% (12.5 mg/kg/day).

    Efficacy of Albendazole Against Experimental Raillietina tetraqona Infection in Chickens
    Abstract of Study:
    Full Study:

    ...Albendazole at dose rates of 2.5 mg and 25 mg per kg per day for 3-7 days, respectively. Seven days from the cessation of Albendazole treatment, all birds in the three groups were slaughtered. Necropsy findings were recorded and blood samples were collected for biochemical analysis. The scientific data presented in this study indicated that oral administration of Albendazole at a dose rate of 25 mg/kg/day for 3-7 successive days, provides an effective treatment against poultry cestodes. The efficacy of the drug was estimated to be 100% as judged by adult warms recovery, faecal eggs counts and by comparison of lesions in treated chicks and infected controls. It is recommended that Albendazole should be used as a drug of choice for effective treatment of R. tetraqona infection in susceptible birds.
    Last edited: Jan 2, 2013
    1 person likes this.
  9. tgooberbutt

    tgooberbutt Chirping

    Dec 24, 2012
    Wow, that is one crazy eBay ad. I'm going to have to do more reading on all of this, but from what I'm finding now, it looks like Albendazole and Praziquantel are use in combination therapy in humans and children to treat tapeworms too (I guess technically that means it's okay to eat the eggs of a chicken under treatment?). In humans, Albendazole does the better job of killing what is in the GI tract and the Praziquantel does a better job of ridding cysts from the rest of the body. I'm not sure what the 'cyst problem' is like in chickens though...the cyst cycle occurs outside of the chicken in an intermediate vector, no? Either way, both seem very effective in ridding tapeworms, and neither seem to pose a big over-dose risk.

    For the Praziquantel, I agree, the 6mg/kg is too low, I'm going to dig further to come up with a better dosage estimate.... Any insight into whether the chickens have to fast before treatment on the Praziquantel? I can't seem to find anything that says they must fast before having Praziquantel administered to them.

    The only reason I'm leaning towards the Praziquantel is because it seems like a one-dose treatment, and perhaps I don't have to fast the chickens beforehand? The Albendazole research is newer, but I haven't seen anything on Praziquantel losing it's efficacy/worms building a resistance? Anyway, still reading....
  10. cowcreekgeek

    cowcreekgeek Songster

    Sep 14, 2012
    Hurricane, WV
    Even though you've made a good point, in that these anthelmintics are used in humans? I still wouldn't eat the eggs for a while ... withdrawal times vary, depending upon which page you're on, but I would also be more concerned w/ the what might wind up in the eggs as the bird digests the dead/dying worms ... there should be studies done for that.

    Oh, and as to the vectors? There some w/ intermediate hosts, and some w/o, and at least on that *is* the intermediate host: Cecal worms are actually the most likely vector of Blackhead Disease ... from Merck's Vet Manual's section of Histomoniasis: The protozoan parasite Histomonas meleagridis is transmitted most often in embryonated eggs of the cecal nematode Heterakis gallinarum, and sometimes directly by contact with infected birds. That last part? Fascinating, as they recently studied birds merely close to one another, and discovered it was transferred from liquid feces by what they refer to as 'cloacal drinking' and ... honest ... I ain't makin' this up ~'-)

    Parasitic diseases (internal)
    Ascarids (Large Intestinal Roundworms)
    One of the most common parasitic roundworms of poultry (Ascaridia galli) occurs in chickens and turkeys. Adult worms are about one and a half to three inches long and about the size of an ordinary pencil lead. Thus, they can be seen easily with the naked eye. Heavily infected birds may show droopiness, emaciation and diarrhea. The primary damage is reduced efficiency of feed utilization, but death has been observed in severe infections.
    Chickens of three to four months of age show resistance to infection. Specimens of this parasite are found occasionally in eggs. The worm apparently wanders from the intestine up the oviduct and is included in the egg contents as the egg in being formed.
    The life history of this parasite is simple and direct. Females lay thick heavy-shelled eggs in the intestine that pass in the feces. A small embryo develops in the egg but does not hatch immediately. The larvae in the egg reaches infective stage within two to three weeks. Embryonated eggs are very hardy and under laboratory conditions may live for two years. Under ordinary conditions, however, few probably live more than one year. Disinfectants and other cleaning agents do not kill eggs under farm conditions. Birds become infected by eating eggs that have reached the infective stage.
    Available drugs remove only the adult parasite. The immature form probably produces the most severe damage. The treatment of choice is piperazine. Many forms of piperazine are produced, and all are effective if administered properly. Piperazine is only effective for treating this parasite. It has no effect on other internal parasites of fowl. Follow the manufacturer's instructions carefully.
    The parasite can be controlled by strict sanitation. If the birds are confined, clean the house thoroughly and completely before a new group is brought in. Segregate birds by age groups, with particular care applied to sanitation of young birds. If birds are on range, use a clean range for each group of birds.

    Cecal Worms
    This parasite (Heterakis gallinae) is found in the ceca of chickens, turkeys and other birds.
    This parasite apparently does not seriously affect the health of the bird. At least no marked symptoms or pathology can be blamed on its presence. Its main importance is that it has been incriminated as a vector of Histomonas meleagridis, the agent that causes blackhead. This protozoan parasite apparently is carried in the cecal worm egg and is transmitted from bird to bird through this egg.
    The life history of this parasite is similar to that of the common roundworm. The eggs are produced in the ceca and pass in the feces. They reach the infective form in about two weeks. In cool weather, this may take longer. The eggs are very resistant to environmental conditions and will remain viable for long periods.
    The cecal worm can be effectively treated with fenbendazole. Since the worm itself produces no observable damage and the eggs live for long periods, it is advisable and necessary to keep chickens and turkeys separated to prevent spread of blackhead.

    Capillaria (Capillary or Thread Worms)
    There are several species of Capillaria that occur in poultry. Capillaria annulata and Capillaria contorta occur in the crop and esophagus. These may cause thickening and inflammation of the mucosa, and occasionally severe losses are sustained in turkeys and game birds.
    In the lower intestinal tract there may be several different species but usually Capillaria obsignata is the most prevalent. The life cycle of this parasite is direct. The adult worms may be embedded in the lining of the intestine. The eggs are laid and passed in the droppings. Following embryonation that takes six to eight days, the eggs are infective to any other poultry that may eat them. The most severe damage occurs within two weeks of infection. The parasites frequently produce severe inflammation and sometimes cause hemorrhage. Erosion of the intestinal lining may be extensive and result in death. These parasites may become a severe problem in deep litter houses. Reduced growth, egg production and fertility may result from heavy infections.
    If present in large numbers, these parasites are usually easy to find at necropsy. Eggs may be difficult to find in droppings, due to the small size and time of infection.
    Since treatment for capillaria is often lacking, control is best achieved by preventive measures. Some drugs, fed at low levels, may be of value in reducing the level of infection on problem farms. Game birds should be raised on wire to remove the threat of infection. As some species of capillaria have an indirect life cycle, control measures may have to be directed toward the intermediate host. Hygromycin and meldane may be used for control. Additional vitamin A may be of value. Effective treatments that are not approved by the Food and Drug Administration are fenbendazole and leviamisole.

    Tapeworms or cestodes are flattened, ribbon-shaped worms composed of numerous segments or division. Tapeworms vary in size from very small to several inches in length. The head or anterior end is much smaller than the rest of the body. Since tapeworms may be very small, careful examination often is necessary to find them. A portion of the intestine may be opened and placed in water to assist in finding the tapeworms.
    The pathology or damage tapeworms produce in poultry is controversial. In young birds, heavy infections result in reduced efficiency and slower growth. Young birds are more severely affected than older birds.
    All poultry tapeworms apparently spend part of their lives in intermediate hosts, and birds become infected by eating the intermediate hosts. These hosts include snails, slugs, beetles, ants, grasshoppers, earthworms, houseflies and others. The intermediate host becomes infected by eating the eggs of tapeworms that are passed in the bird feces.
    Although several drugs are used to remove tapeworms from poultry, most are of doubtful efficacy. In general, tapeworms are most readily controlled by preventing the birds from eating the infected intermediate host. Tapeworm infections can be controlled by regular treatment of the bird with fenbendazole or leviamisole.

    The gapeworm (Syngamus trachea) is a round red worm that attach to the trachea (windpipe) of birds and causes the disease referred to as "gapes". The term describes the open-mouth breathing characteristic of gapeworm-infected birds. Heavily infected birds usually emit a grunting sound because of the difficulty in breathing and many die from suffocation. The worms can easily block the trachea, so they are particularly harmful to young birds.
    The gapeworm is sometimes designated as the "red-worm"; or "forked-worm" because of its red color and because the male and female are joined in permanent copulation. They appear like the letter Y. The female is the larger of the two and is one-fourth to one inch in length. The male gapeworm may attain a length of one-fourth inch. Both sexes attach to the lining of the trachea with their mouthparts. Sufficient numbers may accumulate in the trachea to hinder air passage.
    The life cycle of the gapeworm is similar to that of the cecal worm; the parasite can be transmitted when birds eat embryonated worm eggs or earthworms containing the gapeworm larvae. The female worm lays eggs in the trachea, the eggs are coughed up, swallowed, and pass out in the droppings. Within eight to fourteen days the eggs embryonate and are infective when eaten by birds or earthworms. The earthworm, snails and slugs serve as primary intermediate hosts for the gapeworm. Gapeworms in infected earthworms remain viable for four and a half years while those in snails and slugs remain infective for one year. After being consumed by the bird, gapeworm larvae hatch in the intestine and migrate from the intestine to the trachea and lungs.
    Gapeworms infect chickens, turkeys, guinea fowl, pheasants, chukar partridge, and probably other birds. Young birds reared on soil of infected range pens are at high risk (pen-raised game birds). Some control or reduction in infection density (worms/bird) is achieved by alternating the use of range pens every other year and/or using a pen for only one brood each year. Tilling the soil in the pens at the end of the growing season helps to reduce the residual infection. Treating the soil to eliminate earthworms, snails and slugs is possible but the cost is usually prohibitive.
    Gapeworms are best prevented by administering a wormer at fifteen to thirty day intervals or including a drug at low levels continuously beginning fifteen days after birds are placed in the infected pens. One drug that is effective for eliminating gapeworms is fenbendazole, however, its use is not presently approved for use in birds by the Food and Drug Administration.
    Parasitic diseases (external)
    Poultry Mites
    All classes of poultry are susceptible to mites, some of which are blood-suckers, while others burrow into the skin or live on or in the feathers. Others occur in the air passages and in the lungs, liver and other internal organs. Poultry mites cause retarded growth, reduced egg production, lowered vitality, damaged plumage and even death. Much of the injury, consisting of constant irritation and loss of blood, is not apparent without careful examination.
    Of primary concern to the poultryman is the Northern Fowl Mite (Ornithonyssus sylviarum) which is a frequent and serious pest of chickens. Heavy infestations result in low condition of the birds and lower egg production, as well as a scabby skin condition. The mite remains on the bird and does more damage than any other species of mite. The mite does not leave the host bird, as do may species of mites, and can be observed on birds in large numbers during daylight hours. It prefers the feathers below the vent and around the tail, but can be found on all parts of the body. The mite is extremely small and a microscope or magnifying glass may be needed to see it.
    The female northern fowl mite lays eggs on feathers where the young mites complete their development without leaving the host. Since they remain on the fowl most of the time, treatment of the birds is necessary to destroy the mites.
    The Common Chicken Mite (Dermanyssus gallinae) is the most common mite found on all types of poultry. It is a blood-sucker, and when present in large numbers, loss of blood and irritation may be sufficient to cause anemia. Egg production is seriously reduced.
    This mite feeds at night, and usually remains hidden in cracks and crevices during the day. It attacks birds at night while they are on the roost. In heavy infestations, some mites may remain on the birds during the day. About a day after feeding, the female lays eggs in cracks and crevices of the house. The eggs hatch and the mites develop into adults within about a week. During cold weather, the cycle is slower. A poultry house remains infested four to five months after birds are removed.
    Since the mite feeds on wild birds, these birds may be responsible for spreading infestations. However, it is more likely that spread of the mite is promoted by using contaminated coops. Human carriers are also important. Since these mites do not stay on the birds during the day, apply treatments to houses and equipment as well as the birds.
    The Scaly-Leg Mite (Knemidocoptes mutans) lives under the scales on feet and legs of poultry. It also may attach to the comb and wattles. It causes a thickening of scales on the feet and legs that gives the impression that the scales are protruding directly outward, rather that laying flat on the limb. It spends its entire life cycle on the birds and spreads mainly by direct contact.
    The Depluming Mite (Knemidocoptes laevis, variety gallinae) causes severe irritation by burrowing into the skin near the bases of feathers and frequently causes feathers to be pulled out or broken. The mite is barely visible to the naked eye and can be found in follicles at the base of the feathers. The mites crawl around the birds at times, spreading from bird to bird.
    The most effective treatment for all mite species is a regular inspection and spraying program of both the birds and their premises. An appropriate solution of permethrin, when sprayed on the birds, will eliminate all mites that infest the bird. The spraying of all facilities will ensure that any mites hiding in cracks and crevices will be destroyed. The treatment should be repeated on a one to two month schedule or whenever populations of the mites are detected.

    Poultry Lice
    The primary effects of lice on their hosts are the irritations they cause. The birds become restless and do not feed or sleep well. They may injure themselves or damage their feathers by pecking or scratching areas irritated by lice. Body weight and egg production may drop.
    All lice infecting poultry and birds are the chewing type. Mites may be confused with lice, but mites suck blood. In general, each species of lice is confined to a particular kind of poultry, although some may pass from one kind to another when birds are closely associated. Chickens usually are infested with one or more of seven different species; turkeys have three common species.
    All species of poultry lice have certain common habits. All live continuously on feathered hosts and soon die if removed. The eggs are attached to the feathers. Young lice resemble adults except in color and size. Lice differ in preferred locations on the host, and these preferences have given rise to the common names applied to various species.
    In general, the incubation period of lice eggs is four to seven days, and development of the lice between hatching and the adult stage requires about twenty-one days. Mating takes place on the fowl, and egg laying begins two to three days after lice mature. The number of eggs probably ranges from fifty to three-hundred per female louse.
    As the name suggests, the Head Louse (Cuclotogaster heterographa) is found mainly on the head, although it occurs occasionally on the neck and elsewhere. It usually is located near the skin in the down or at the base of the feathers on the top and back of the head and beneath the beak. In fact, the head of the louse often is found so close to the skin that poultrymen may think it is attached to the skin or is sucking blood. Although it does not suck blood, the head louse is very irritating and ranks first among lice as a pest of young chickens and turkeys. Heavily infested chicks soon become droopy and weak and may die before they are a month old. When the chickens become fairly well feathered, head lice decrease but may increase again when the fowls reach maturity.
    This louse is oblong, grayish and about 1/10-inch long. The pearly-white eggs are attached singly to the down or at the base of the small feathers on the head. They hatch within five days into minute, pale, translucent lice resembling adults in shape.
    The Body Louse (Menacanthus stramineus) of chickens prefers to stay on the skin rather than on the feathers. It chooses parts of the body that are not densely feathered, such as the area below the vent. In heavy infestations, it may be found on the breast, under the wings and on other parts of the body, including the head.
    When the feathers are parted, straw-colored body lice may be seen running rapidly on the skin in search of cover. Eggs are deposited in clusters near the base of small feathers, particularly below the vent, or in young fowls, frequently on the head or throat. Eggs hatch in about a week and lice reach maturity within twenty days.
    This is the most common louse infesting grown chickens. When present in large numbers, the skin is irritated greatly and scabs may result, especially below the vent.
    The Shaft Louse or small body louse (Menopon gallinae) is similar in appearance to the body louse, but smaller. It has a habit of resting on the body feather shafts of chickens where it may be seen running rapidly toward the body when feathers are parted suddenly. Sometimes as many as a dozen lice may be seen scurrying down a feather shaft.
    Since the shaft louse apparently feeds on parts of the feathers, it is found in limited numbers on turkeys, guinea fowl and ducks kept in close association with chickens. It does not infest young birds until they become well feathered.
    The same control measures used to eliminate mite populations is effective for treating lice. It is more important to apply the insecticides directly to the bird's body rather than the premises.

    Fowl Tick (Blue Bug)
    The Fowl Tick (Argas persicus) may be a serious parasite of poultry if it becomes numerous in poultry houses or on poultry ranges. The tick is a blood-sucker, and when present in large numbers it results in weakened birds, reduced egg production, emaciation and even death. The fowl tick is found throughout most of the South and is extremely hardy. Ticks have been kept alive without food for more than three years. The ticks will feed on all fowl.
    Fowl ticks spend most of their lives in cracks and hiding places, emerging at night to take a blood meal. Mating takes place in the hiding areas. A few days after feeding, the female lays a batch of eggs. In warm weather the eggs hatch within fourteen days. In cold weather they may take up to three months to hatch. Larvae that hatch from the eggs crawl around until they find a host fowl. They remain attached to the birds for three to ten days. After leaving the birds they find hiding places and molt before seeking another blood meal. This is followed by additional moltings and blood meals.
    Ticks are difficult to eradicate and methods employed must be performed carefully. It is not necessary to treat the birds, but houses and surrounding areas must be treated thoroughly.

    Chiggers, Red Bugs or Harvest Mites
    These pests (Trombicula splendens, Trombicula alfreddugesi, and Neoschongastia americana americana) attack chickens and turkeys, as well as humans. Normally these small mites feed on wild animals, birds, snakes and lizards. Only the larvae of chiggers attack poultry or animals; adult mites feed on plants.
    Larvae usually attach to the wings, breasts and necks of poultry. They inject a poisonous substance that sets up local irritation and itching. After a few days, the larvae become engorged and drop off. Injury to grown fowl may not be apparent or noticed until the bird is dressed; then the lesions are readily apparent and greatly reduce the carcass value. Young chickens or turkeys may become droopy, refuse to eat and die. Due to methods of raising poultry, turkeys are more affected than chickens.
    Control of External Parasites
    There are many insecticides available to help control external poultry parasites. The most effective broad spectrum insecticide is permethrin. Permethrin has a significant residual activity, thus making it ideal for treating facilities and equipment. At reduced concentrations it can be applied to the bird. Follow all manufacturers recommendations when using all insecticides.

    But, back to gettin' rid of these things ... one concern, esp. when infestations are most severe, is the speed at which the worms might become disabled ... notably, one of the studies (yours or mine; can't recall which) actually determined the time before one type of worm was affected by the anthelmintic, which might help me to encourage some research into a better way; one that, for certain, eliminates the worms, but sheds 'em in such a way as to provide no opportunity for blockage, or the rush of proteins.

    Neither Apple Cider Vinegar (ACV) nor Dimetomaceous Earth (DE) have been proven as effective anthelmintics. However, they have both been proven to be useful as preventive measures, and to help reduce the loads. Although the slight acidic environment that ACV creates is more hostile to internal parasites, there's a study on tannins as an alternative that might shift the credit towards the apple the vinegar's made from.

    The study can be seen here: Anthelmintic Effects of Condensed Tannins

    There are so many studies that indicate what could become a more certain, and far gentler/safer, manner to eliminate worm. There one that's not gonna be done 'til April, in which they're treating rats and pigs orally with Bt-Cry proteins to evaluate the clearance of one gastrointestinal nematode, but it's things like this that might prove most useful. Not, of course, for this time 'round ... you've got tapes in your flock? Get 'em out. Now. But, for down the road, and for all the BYC community? It's sure worth puttin' in a few extra hours of study, and even longer ones of deeper thought ~'-)

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