We have a flock of six. One by one over the past few months our hens have started losing feathers. At first I suspected it to be them sorting out their pecking order even though we haven't noticed any fighting or aggressive behavior. I now suspect their may be something more, possibly a mite infestation. Outside of the feathers missing they act normal - eating and laying regularly. The feather loss has started around the base of the tail feathers on the back. It slowly has moved around the bottom egg duct area. A couple even have feathers missing around their necks. There is some redness in the bare areas. I recently purchased from the local Tractor Supply, 'All Natural Poultry Protector' by Manna Pro and thought rid give it a try. Any ideas on the issue and a solution?