Hey everyone, the important thing to remember about MG is that it is quite easily treatable and the vast majority of birds recover. Yes the whole flock will probably be infected, and yes they will all be carriers for life and have the occasional relapse, and yes it will transfer through their eggs to any chicks you wish to hatch, but here in the UK, most backyard flocks have it - it is simply an accepted part of poultry keeping. It's almost considered as common as worms... ie a condition which you have to manage and if neccessary treat reactively, rather than try to eradicate completely through drastic measures such as culling/restocking.
I have absolutely no intention of culling my beloved Henrietta just because of a sniffle she had three months ago. She is completely recovered and very healthy and has a great life. Her companion Bella actually never showed any signs of disease, although we think that as a hatchery bird she had been immunised against MG as a chick. And we are lucky in that there are only the two of them, and we treat them as pets - hence we don't really care about hatching chicks or selling eggs or otherwise making money from our girls.
Anyway, my point here is that MG is only a total disaster in a flock if you want to make it that way. So don't be downhearted sarahs31 - your chicken(s) will most likely completely recover and your flock can carry on as normal, as long as you don't mind the odd relapse, you don't want to use your girls for breeding etc, and you accept the risk of any new birds you bring in picking up the MG too (and needing the Tylan treatment).
I just wanted to offer you a positive opinion on mycoplasma! It really needn't be the end of the world...
(Oh, and I'd seriously doubt it was something in her eye by the way - the foamy stuff that you see in chickens' eyes comes from the sinuses, which are directly located adjacent to and beneath the eye socket. Only a respiratory disease would cause the sinuses to foam up, not a foreign body in the eye. Sounds like classic mycoplasma to me.)