I have 10 chickens in a covered shed(6'x10')with 8'x12'outside run. I clean 1x week(simply empty straw ,add new straw at end of day) I was in w/chickens today and started itching(i know-i am probably bad) and noticed teenie tiny things crawling on me(i treated them with powder 2x a couple yrs ago because of "same" thing) is this happening simply because i have not cleaned often enough or is it something that you just keep under control and they carry them anyhow?? they are fully feathered and appear unirritated. i am going to powder them/shed in the morning and let them free range. GROSS.