I have 1 1/2 old hens that have been laying great. They are all starting to loose feathers on their butt and one has lost feathers on butt and back. I do not run a rooster. This happened on the last batch of hens I had. Everyone told me I had a feather picker. So these are now new and I have watched and do no see feather picking happening. I am feeding TSC brand crumble layer and scratch grain. This is all I provide them besides now that spring is here some cut grass. I am thinking this is nutritional issues VS feather picking. Any thoughts?