We have 5 *9* week old chickens, and I am finding numerous adult feathers in and around their coop. They seem happy, and don't have obvious pecking order disputes going on, but I cant figure out why they are losing their adult feathers. Could they have mites? Where on their body would I look to see if they have them? Is it something that would be obvious, or will I need a magnifying glass? They do seem to be preening themselves an awful lot, or maybe they are just trying to itch where the mites are? Help please!!