Approximately 4 weeks ago one of my hens (9 mo.) started limping...moved her to separate building. Leg not broken or dislocated, she eats and drinks normally, no diahrea. Gave her Sulmet in her water for 4 days...no change. Then last week a hen and rooster had diahrea...very runny (like water)...rooster is improving but little hen (9 mo.) died last night. 2nd rooster (9 mo.) started limping last week, no diahrea. So now I have two limping chickens and one with diahrea. The Sulmet doesn't seem to help at all. Please help.