Chickens loose feathers every summer, why? (Not Molting)

[jloftin60]

My uncle has some 25 different chickens, but he as 6 or 7 Dominiques who loose
all their tail feathers every summer. Their whole back end is red skin and no feathers
all the way up their back. The other chickens don't loose their. After
they molt and winter time comes, they refeather.

 

[Chicabee19]

Does your uncle have a rooster?

 

[jloftin60]

Yes, he does have a rooster. The area of feathers missing is too large for rooster
damage.