We started a chicken coop. Started with 35 chicks. (In April)learned about the Cornish cross the hard way. (Had 10 one by one 4 died & the remaining 6 got easily 12 to 14 lbs before I gave them up. They took up too much room & caused stress with the rest of the flock.) The 5 barred rock turned out to all be roo's. Gave 1 away & still have 4. The rest RIR hens. Have the nice moveable coop. Lately the hens combs went pail & had bloody stool. So far we have lost 4. 3 as soon as the comb turned pail they were dead in less than a day. The last one from pail to purple and dead.called vet. They don't deal with chickens... so I asked the people at the feed store. (With Corid in hand) they said if I did that I'd kill them. And recommended a tetracycline. So I have been doing the tetra... but it isn't taking care of it.(this is day 5 on the tetra) the chickens still eat fine. But more combs are pail & it looks like everyone but the roo's have the runs. (Not so much blood in the stools but still trace amounts.) Bought corid today. Waiting to see if anyone knows... good idea? Bad idea? How soon after tetracycline? (as I gave it as per directions today)I guess the chickens are now about 5-6 months old. And I clean the coop 4to 5 times a week. (Mainly free range during the day up at night. But have kept them in the coop this last week.) I just as soon treat all instead of guessing 1 chicken at a time.