Your Questions: Answered

How do I know if my chickens have lice?

Typical signs that your chickens may be suffering from poultry lice, could be as simple as a change in their behaviour or character. They may look pale or anaemic, they may be scratching or plucking at their own feathers or they could be refusing to enter the coop at night.
If you have concerns then the best way to check for Lice is to part the fluff around the vent area and search as the base of feathers for white eggs or black critters the size of a sesame seed.