You definitely need to get rid of all
except one rooster. Otherwise they will end up killing the hens, while making their lives miserable in the meanwhile. It’s part of being a good chicken “Mom.”
As a fan of "The Incredible Dr. Pol" (a tv show about a veterinarian in Michigan), I would suspect coccidia, an intestinal parasite that can be fatal. Maybe can buy meds at the farm store????
