I noticed today that my Ameraucana Bantam has lice. They appear to be head lice because I saw two running on top of her feathers (no signs of sores on her skin at the base of her feathers). My other chickens (I have 8 total) appear to be lice free. What's the best way to treat the lice? Should I just treat this one hen or the whole flock? My chickens free-range when I'm home in the evenings and on the weekends during the day, but the rest of the time they are together in a large inside coop. In case this matters, this hen (the one with lice) is just over 1-year old. I have two other hens that are the same age. The other 5 chickens are 18 weeks old on Monday (7/5/10).