Greetings thatdude,
These insects (mites), exist in the environment, they are spread by wild birds. It was found that, Fowl mites studied by H.P. Wood, contributor "Vintage Farming Classics, Poultry Parasites"; in dry Summers they can live 56-85 days without food, and under moist Winter conditions up to 113 days.
In the case of Scaley Leg mites, leg scabs that are torn off the infected chicken, liberates masses of the parasites, which during Summer weather, can live in accumulated filth in the coop, away from the chicken for up to a month.
yikes! As you can see, it is critical to stay on top of these pests, for the health of the chicken. The author also states that in acute cases the chicken will become thin, and may even die.
So there you have it, I hope this was helpful.
God Bless
