Older hens may have Mycoplasma, planning to add 2 new chicks to flock, what do I do?


7 Years
Oct 27, 2014
I have two mature (around 6 years old) black laced wyandottes in my backyard coop. And have two young (3 week old) bantams (forget the breed at the moment) in my garage chick enclosure.

I noticed one of the wyandottes sneezing or gulping a lot yesterday (something they have done before) but it seemed a little more severe. As I got close to inspect I could see she had small bubbles around both eyes. My reading suggests this is Mycoplasma. The other hen seems ok for now. But I suspect this has is probably not a new ailment to our coop, I just never noticed it before.

My question is, how do I proceed with introducing the new hens in a few weeks? Do I need to cull the older chickens in order to keep the chicks safe? Is the standard treatment of Tylan enough to keep them all healthy? Are eggs from these chickens safe to eat?
If you have one chicken with a respiratory disease, then your whole flock would be considered carriers for life. Tylan can treat symptoms of MG, but it does not cure it or keep the chicken from being a carrier. If you have handled your bantams after being around your older hens, they could allready be exposed. Most people do well to close their flocks to new birds, and never rehome or sell birds when they have a chronic disease. There is a vaccine available, but it is simpler to close the flock. You could cull the sick bird, and send her body into the statte vet for a necropsy which would tell you if she has MG. Any time you buy birds or chicks from another person and not get chicks from a hatchery, you have the risk of bringing in diseases. Here is a list of most state vets where you can get a necropsy:

Here is some resding about MG:
https://extension.umd.edu/sites/ext... Mycoplasma gallisepticum (MG) Infecti....pdf

Thanks for the links. I've found more or less the same info in a few other places as well. The sick hen seems fully recovered this morning. This is typical of any other occasions I've seen them sneezing or with runny beaks. It's gone in about 24 hours. We hag out near them, let them out around us in the backyard often, but rarely handle them anymore. So I think the chicks are ok, uness they came infected from the breeder. The likely source for us is either rats (or squirrels and raccoons, all present in our backyard to some degree). Or wild birds, some of which can get into the coop. the chickens had a yard waterer that other wild birds used, but I just removed that.

Starting to give them all ACV in water today. Looking at Tylan Soluble for treatment and Virkon or F10 for disinfecting the coop area. Would love opinions experience on any of these.

Still not sure what to do with the birds. I don't plan to rehome any of them. The wyandottes don't lay much anymore. Would like to keep the bantams. But my kids won't be happy with me needing to kill the older chickens to do that. And I suspect the pathogens are everywhere in our backyard anyway (lots of wildlife despite being in an urban area).
They get MG from other poultry or wild birds. You can also track it in on shoes, clothing, etc. Many backyard flocks can test positive for MG, but just keep that in mind when adding or hatching birds (since it can pass through hatching eggs.) Are you adding 2 chicks or older birds? ACV does nothing to prevent MG. I always have several waterers out in my yard in the shade, especially in summertime. They will drink more water if you have it available. You don’t want dehydrated birds, even if wild birds drink. Every day, I clean them out and add a couple of drops of bleach in each gallon bowl. If you use galvenized waterers, do not use bleach or ACV. It is always best to get the number of chicks you want in the beginning, and when they are all gone, wait a few days or weeks, and get new birds. MG lives about 3 days when chickens are gone.
ACV is just for general health benefit, makes me feel like I'm doing something immediate ; ) And yes, I'm aware it's not a preventative for MG (MG once contracted is permanent). They drink from plastic and glass waterers. Suffice it to say, I have all the basic details of MG (and ACV and everything else) at hand. Yes, of course you start with the number of birds you want (as we did with 4 birds 6 years ago, 2 died naturally 3 and 4 years ago). But I think it's impractical to assume you'd wait until all of them dire naturally before you start refilling your flock, especially when you only keep 3 or 4 at a time.

What I'm looking for are practical approaches others have taken or would take that may not be listed on websites with the medical info for MG etc. Had I known my older hens had MG before getting the bantams I wouldn't have bought them. But this only just came up, and we've had the chicks for 3 weeks now. The plan is to introduce them to the coop in another 2-3 weeks. So... what would other do, given the situation I'm in now, (not an ideal fictional situation). Would you cull the older hens? Is that the only solution? Can the bantams be introduced to hens with MG if they are being treated with Tylan? Or should I sell the chicks (who may have been exposed already)?
Also, it sounds to me like MG is pretty common in home flocks. So I have to assume they got exposed early on and have been living with it for some time. This may even be what killed the other 2 hens we started with (both died inexplicably with no symptoms). I also have to assume the if I remove the older hens, the young ones will still be exposed in the backyard at some point.
Has no one here really ever been in the same situation?

I'm getting two different vibes with regard to MG. That its a deadly disease that needs to be kept out of the flock entirely, especially with large flocks (my flock is two chickens currently, with two more in the garage). Or that its a common backyard ailment that can be lived with assuming your birds are otherwise healthy and have not succumbed to the disease on initial infection.
Tylan is only useful to treat symptoms of MG. It is not a preventative. When chickens in the flock test positive for MG others who are added later will probably be carriers. Many people treat sick birds or cull sick ones. Some cull their flocks and start over. There are different opinions. Some may use a vaccine on new birds.
This is the most useful info I've found so far with regard to managing an infected flock: http://www.gapoultrylab.org/wp-cont...coplasma handout for Backyard Flocks 4-12.pdf

My one (possibly) infected bird showed very mild symptoms for only about 24 hours. She never looked anything like the images of much sicker birds. I think I'm going to do a deep clean of the coop and run, and just introduce the new birds in a few weeks and see what happens.

"Treat and Manage
There are several antibiotics that may be used to treat Mycoplasma infections although none of them will cure the
disease or completely prevent transmission to other birds. Treatment may decrease the birds’ symptoms, help them
recover faster, and help decrease transmission to new birds. Treatment may need to be repeated monthly to keep
Mycoplasma at low levels since the positive birds will carry it for life.
The antibiotics used to treat Mycoplasma include erythromycin and tylosin, and tetracyclines, such as oxytetracycline
and doxycycline. These are commonly available in feed stores, on the internet, and from poultry supply stores and
catalogs under brand names such as Gallimycin, Tylan, Tylovet, OxyTet, BioMycin, ChlorTet, Duramycin, Terramycin,
Doxyvet, and others. Most are available in either oral or injectable solution. It is very important to follow all instructions
for poultry on the label and observe the withdrawal times listed.
In addition to treating the birds with antibiotics, the disease will have to be managed for the life time of the flock and
any new birds may become infected. Strict biosecurity measures (separate clothing, shoes, and equipment, footbaths,
restricting access, etc.) will help prevent spread of Mycoplasma from your flock to others. Also, no birds from a positive
flock should be taken to shows, auctions, flea markets, or exchanged with friends and neighbors. It is important to
remember that even if only a few individual birds test positive, any other birds in the flock may be carrying the disease
and should be considered positive also.
If you decide to keep and treat your flock, keep in mind that the disease may reappear at any time and new birds added
to your flock will eventually become positive. It is your responsibility to keep Mycoplasma from spreading to other
flocks and especially to nearby neighboring flocks, including commercial poultry farms."
My closed flock currently has a host of crappy diseases, MG being one of them. It is common and it isn't deadly. Or at least generally not on its own. It can reduce laying in birds and make them unthrifty by making them more susceptible to other illnesses and parasites. But it's generally not a killer. I think because it's so insidious is how it's so prevalent.

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