I have some Splash Silkies. The hens are loosing the feathers on the top of their heads (Crest), and their tail feathers are also thinning. I am wondering if this is from the Rooster? There are not missing feathers on their backs or wings, could it still be from the rooster? My rooster is 2 years old, and fairly big compared to the hens. He is not aggressive to the hens at all. What do you think I should do?