Well we have had chickens now for about 10 years and have learned a few things about chickens that might help you even though we live in Australia.
Ours got mites. little black things on parts of the chickens body that isnt covered by fur..we got told we had to by this insecticide and hold the chickens by their legs (poor chickens) and dunk them in a bucket full of insecticide which they didnt like and we didnt like doing. We finally found another method which works just as well. You get vaseline (petroleum jelly which you use on your lips etc)and smear liberally all over the mites and it suffocates them. The way to avoid mites is to have a coop off the ground and with a floor as since we built the new coop we have had no problems. When building your coop think of ease of getting in there and cleaning it out, ours opens up on one side and we have a little door for the chickens to get in and out with a ramp so they can get up there as our coop is about a metre off the ground. Also they eventually eat and scratch there way to a coop that is all sand and no grass etc so we built our coop with a run on each side so when one side is exhausted we put them in the other side to let the other side recover. I usually throw out wheat and let it grow and let them in there when it is about knee high and they love it. We also have a problem with crows stealing eggs as our coop is not covered so if you have crows you should maybe think about covering your coop. We also had foxes kill our chickens but again had no problems now that we have dug in tin to about 1/2 a metre deep all around but wire would do the same thing. I love my chickens and enjoy sitting outside just watching them scratching away just something that makes me feel so relaxed...our chickens are like a pet and live out their days as i could never ever kill one..wish you all the best with your chickens and if you have any other questions dont hesitate to ask.
Helen