Recently, I have lost several chickens to some sort of progressive weakness. It has affected all of my Polish (except for the frizzle) and I have lost the two hens. The two cockerals have good days and bad. One has a wry neck. I have lost one cochin to it, he eventually just wasted away, and the second (his brother) was at the good day/bad day point (until he was attacked and killed by the other chickens yesterday - so I don't know if he would have recovered or not). It also killed one of my Am roos. Now, one of my Am pullets seems to be affected. would really like to be able to save her and the two polish roos that have it, as well as prevent it from spreading... So, here are the symptoms: progressive weakness (NOT paralysis) pullets just get weaker and die, cockerals seem to lose more bodily control & get wry necks affected birds WILL try to eat and drink NO upper resipiratory symptoms, clear eyes, no mites (that I can tell) maybe diarrhea - hard to tell, b/c by the time I realize a bird is affected (basically, b/c I can catch it), they don't eat well & therefore don't poop well eventually death - although some seem to be hanging on longer than others Here is what I have tried: Sulmet Wazine tetracycline electrolytes I have also tried Ivomec, with mixed results - the Am roo I gave it to died, but the Polish cockeral I gave it to is still alive...with a wry neck. I should also mention that all of the affected birds are from two specific breeders, although I'm not overly sure that's relevant. What am I supposed to try next???