That is so sad! Sounds like you have an offending alpha hen inspiring all the hens into injurious behavior. Are they all penned or are they free-ranged? He probably can't get away from the hens ganging up on him! Or he may just be a timid soul that doesn't have the personality to get away from the hens. Sometimes it takes one mean hen to spread contagious behavior to the other hens -- just like feather-picking or egg-eating can spread throughout a flock if the offending leader isn't nipped in the bud and removed immediately. We had to remove a feather-eating Marans out of the flock when we realized a Silkie wasn't molting but being eaten alive on the roost at night! The Marans was a very nasty tempered hen, challenging and combating the alpha White Leghorn, chewing the docile Silkie on the roost at night, and openly clawing and fighting another little timid Silkie. I don't introduce heavy, large, or dual-purpose breeds into the Silkie flock any more. Ameraucana and Breda are the only two gentle docile breeds we found compatible with our timid Silkies. Polish, Sultans, Easter Eggers, Cochins, and other breeds are gentle too but we have limited zoning; otherwise I would have those breeds too.