How do I know if my chickens have Northern Fowl Mite?

Because Northern Fowl Mites live on the chickens, if there is an infestation will you will be able to see them or their eggs if you regularly examine your chickens. Lice are small brown critters; Northern Fowl Mites are smaller and black. Both lice and Northern Fowl Mites feed off your chickens’ blood, which makes them irritable and grumpy; they may peck each other or pull out their own feathers. Infested birds may also look pale and may stop laying for no reason.