I'm glad this topic came up, because I would like some advice from folks regarding how to handle a possible Mycoplasma issue. Especially as it relates to keeping rare breeds and showing (or not showing) birds. My own situation is described a couple of paragraphs down.
From what I have read, the only way to get rid of Mycoplasma gallisepticum ("MG") is to cull all your birds in the affected areas, keep the space bird-free for a couple of weeks and start over with a disease-free flock. Depending on how your birds got it in the first place there is no guarantee they won't get it again - especially if your birds are in contact with wild birds, which are one potential source of the disease. After the initial infection the organism remains in the chicken, and can be transmitted to other birds via close-range airborne transport, or physical transport. It can be transmitted via eggs and equipment. It has a short life outside of a bird, so if you get rid of all your birds and keep the area free of birds for a couple of weeks it should be gone. Since a lot of commercial poultry operations use an "all in, all out" process, replacing all the birds at the same time, they can deal with MG infections by leaving the facility to rest for a brief time before importing a new batch of birds. This procedure works for egg farms, but is problematic for operations with multi-age flocks like hatcheries and small scale breeders.
If you are a small scale breeder it can be a dilemma how to proceed. If you keep your multi-age flock the organism will always be present in the flock. You can use antibiotics but most of us breeding our own birds are trying to avoid antibiotic use. You can gradually select for more resistant birds (breed only the birds that don't appear to get infected.) But the birds you have will likely be carriers - unless you kill them all, wait a period of time and start over. Which kills your whole breeding program up to that point. Which you may not be willing to do if the breed you are working with is relatively rare.
This is a timely issue for me because I now suspect my flock had a run of Mycoplasma this summer. Back in June when my birds were about five months old, virtually every bird in my flock got the sniffles for a day. Very mild, looked like a mild cold would look in a human - some sneezing, a few birds had a minor discharge - and it lasted 24-48 hours. I noticed the first bird sneezing one afternoon and was going to cull the bird the next day - except that bird was better in the morning, and the other birds were sneezing. So I did not cull any birds because I would have had to cull them all and it didn't seem serious. They all got over whatever it was in a day or two and seemed fine. They still ACT fine. But during our first big summer monsoon in July all the cockerels were standing in the yard - soaking wet, in the rain - they had shelter available and didn't use it - and the back edges and tips of all of their combs were purple. They looked like little kids who had been playing in the ocean so long their lips turned blue. The combs went back to normal color after the birds dried off and warmed up. I was concerned but didn't stress over it. Now the weather is cooling off here - nights in the low 40's, days in the high 80's - and their combs have a tinge of purple in the early morning. They are normal color again by mid day. Hmmm...
I didn't put any of this together with Mycoplasma until a few weeks ago. In early September I butchered a couple of cockerels. One had a normal liver, as had all the other birds up to that point. The other cockerel had a weird, gray liver. The liver had a matte gray coating, with a few spots of normal-liver surface showing through. It was the weirdest thing I ever saw and I am still kicking myself for not saving the liver for testing, or even getting a photo of it. Since then I have been combing resources to find out what that liver issue could be. I found the Cornell University site, and the liver photo (#15 of 21 under Gross Lesions under Mycoplasma gallisepticum - see link below) is very close to what I saw in my bird. Uh oh. And it turns out purple comb edges are a symptom of Mycoplasma infection. In hindsight, the round of sniffles this summer was probably a mild case of MG.
I was hoping to show my birds next month but I don't want to show them if they are carrying Mycoplasma. I need to get them tested. And if they do carry Mycoplasma now, as I suspect, then what do I do? I have no idea where they got it, unless it came via the wild birds in my yard, and there is no way I can keep them separated from the wild birds. My current birds are great for a backyard flock that is somewhat resistant to stuff on my property - it was a mild case. The birds have not been significantly affected in terms of vitality or production. But I won't feel right about trading breeders with anyone, or selling chicks. Or showing birds that are potential carriers.
There is only room for one breed on my property. Culling the affected birds means culling the entire flock and starting over some time later. I am reluctant to do that but will if it is necessary. I'm glad this topic came up, because I would like some advice from folks regarding options for handling this issue. Especially in terms of showing birds.
Here is some more information on Mycoplasma. It is geared for commercial poultry, but it explains the issues in relatively plain English:
http://edis.ifas.ufl.edu/ps034
For a more technical explanation designed for veterinarians and people doing necropsies, this Cornell University College of Veterinary Medicine site is fascinating:
http://partnersah.vet.cornell.edu/avian-atlas/search/disease
Thanks for any insight you all can give me.
Sarah