My flock of 10 hens all have naked, nearly naked or soon-to-be naked bottoms - meaning there are no feathers from just below their vents down to their sternums. (There are feathers all the way around the vents.) This happened two years ago and the baldness eventually spread to most of their bodies. While all of this was going on, they continued to lay eggs at a normal rate. I sent feathers and droppings off to my local extension service and they reported there were no parasites detected. After nearly six months, they started to regrow feathers until they all looked beautiful again but, guess what? No more eggs! I finally gave up and reluctantly sent them to chicken heaven. After cleaning the hen house thoroughly and letting it sit empty for several months, I restocked with a new batch of chicks last spring. They are laying eggs just fine but the naked bottoms are making me despair. I have carefully inspected the bald spots and cannot find any sign of mites or lice. I feed the flock layer pellets and use pine shavings for bedding. The first five/six years I raised chickens, this never happened. I would really appreciate some advice. Thanks. Worried in Alna Maine.