Your friend should check the chickens for bugs, before getting new ones. I find it is easieast to take the chickens off the roost at night and check: around the poop shoot, around the oil gland on the tail between the legs, under the wings and on the neck. Most of the critters move pretty darn fast once they are exposed to light and are close to flesh or skin colored. So you have to look for tiny movement. Different critters reside on different parts of the body and to make matters worse, some only occupy the chicken at night.
It hardly matters what is what, if you see little critters moving, it is best to deal with it.
I give my birds "flea" baths, dust with diatomaceaus (sp) earth, provide wood ashes and sometimes use other flea products. A lot of people use Sevin. I react badly to it, so I won't use it.
Flea products that are safe for kittens work and are safe on chickens, but you are not supposed to eat the eggs or the meat, because the effects have not been studied.
I don't think the shaking head thing has to do with bugs though. I think there is something else chickens get, that causes them to shake their heads. Maybe someone else has more info.
