You know, I'd sure get her going on a good de-lousing program asap. Give her a nice bath with Adam's Plus Flea and Tick Shampoo. It's always handy to have their spray around too. Blow dry her and put her some place where she won't catch a chill overnight. Dust her with Sevin for a couple weeks every week. If she's not been in a worming program, it would be a good time to start. Find some Valbazan and give her (if she's an average sized hen) 1/2 ml or cc orally. A smaller breed more like 1/4 ml or cc orally. Thing is in another week you could use Ivermectin pour on at a dose range of something like 3-7 drops depending on the size of the bird. That stuff kills mites and lice (but only the blood suckers). Do that one time and repeat in a couple weeks. Follow each with Sevin (which will kill the deplumers). You can use the flea spray around the ears and ear lobes and underneath the waddles (for ear mites and the deplumers). I also would either spray the legs with the flea spray or coat the legs with oil (I like the Scarlet Oil). You might need to ask for a spray top for it. Sometimes it comes without that. But Scarlet Oil is also a very good wound treatment. You can put the sevin powder on and spray the Scarlet Oil over the powder if you wish. Avoid getting any of this stuff in the eyes and avoid having the chickens or yourself breath the Sevin. PS: Normally when you do a round of Valbazan, you repeat in 7-10 days. You can repeat the dose when you do the Ivermectin pour on. Valbazan kills alot more internal parasites than the Ivermectin so you might as well take advantage of it. Thing is, internal and exernal parasites are a double whammy for feathering, appearance and overall health.
