I have a large coop and run the coop is covered and clean, the run is not covered but pretty clean. . . when it rains there is an area that gets muddy. My leghorns lay in the mud and then pluck their chest feathers out!!! The rooster is now drooling, and panting very hard. none of the other chickens do this I have wormed them, checked for mites, seven dusted the entire coop and run all the other birds are fine but the leghorns all three of them are doing this weird thing!!!!! Should I cull them I don't know what the problem is I lost one a week ago but her chest was completely eaten away!! the others seem fine VERY Confused!! the birds are indeed Cornish crosses!! they are HUGE!! I transported one to a friends house and he almost had a heart attack on the way!! She will come get the rest of them I do not eat my birds. They on the other hand do and I am ok with that. The rooster has to be more than 12-15 lbs and the hens are not far behind. I know the food will last longer when they have been sent to meet the pot. thanks for all your help!