Hi farmhand,
First thing I noticed was some head twitching among the birds. I read up on the potential causes and it looked like it might be mites. I inspected the birds and didn't find anything. Their combs were very pale but since most of the birds in that coop were young I just took a watch and wait approach. When some of my adult birds started showing signs (combs turned pale and started drooping) I started thinking that they definitely had mites. I checked them again but didn't see any of the telltales signs... in fact I've never seen a single mite even to this day. By this time the birds seemed like they weren't growing as well as expected and I started some spot treatments with poultry spray and regular pen cleanings. I started noticing that I would get itching when entering the coop and the birds didn't really seem to be improving very much. I stepped up the chemical treatments as follows, first permethrin spray, then garden and poultry powder sprinkled throughout the litter and coop. No real success. I used some flea and tick bombs with nylar, sevin powder, etc. slowed them down but no real lasting effect. I sprayed the entire inside of the coop with sevin, used poultry and garden powder, equine spray.... still no real lasting effect. I was also now tracking them into the house each time I came back from the coop. (Still dealing with that problem but seems to be resolving.... slowly). Finally after a lot more research I decided to use a long lasting pour on treatment. I chose cydectin (moxidectin) since it came in a pour on form, has 30 day control and mites have not shown resistance (at least in what literature I could find) to the active ingredient. The dosing seemed to be forgiving as well. I tested it out on several birds of different sizes using 1 ml per kg of bird. I applied it with a 3 ml syringe (without the needle) to the skin under the wings. No ill effects were noticed so I treated all my birds. While not labeled for chickens I found some literature suggesting a 5 day withholding period but decided on holding eggs for 2 weeks. There is no withholding period for sale of meat in cattle and other animals but I figured better safe than sorry. This treatment has the added benefit of deworming as well. This treatment has shown great promise but didn't solve the problem completely. I plan on spraying them with poultry protector every other night going forward while treating their litter with alternating applications of garden and poultry powder and sevin. I will do this for the next few weeks and then follow-up with a treatment of Revolution as suggested by Ron. I am also going to install dust boxes in each pen filled with wood ashes and treated with sevin. I need to get to a vet so I can get a prescription though as you cant buy it without one. Not sure what the control period is for Revolution but I will continue to spray with poultry protector and treat the litter. I will then follow-up with one more round of cydectin if required. You ask what I would do differently..... Get on the problem immediately don't wait a day. Provide you birds with a way to give themselves dust baths. These breeding pens do not give the birds access to the outside and I think the lack of access to dust baths is a major contributor to the problem. I would look into a systemic control early on. Revolution seems to work well and if the weather is warm should be able to knock down successive generations of mites... which is necessary for total control. Finally, make sure your cloths, house, car etc don't act as a reservoir for mites. They will live for an extended time off the birds and can (and will bite humans). I take my clothes off immediately after going into the coop and treat with insecticide on a regular basis. I shower immediately after coming into the house as well. These things are insidious and shouldn't be taken lightly. The past 4 months have been really stressful and taken away a lot of the enjoyment of owning chickens. I don't even let my family go into this coop at this time. I am feeling optimistic that I've got a solution now but there are still no guaranties.
