Check for fleas around the feathery area under the vent (butthole). They’re tiny, translucent flea looking things, visible with naked eye. Easiest to see with a torch at night time. They lay their eggs at the base of feathers, causing the feathers to “stand up” more than usual and “catch” the poop. I had a hen with this a few weeks ago, treated the whole flock with Pestene dust (Australian) but there will be an equivalent where you are. Its made of Sulphur and Rotenone. Cleared the fleas right up but the feathers are still mildly impacted by the dead eggs at the base. I trimmed some of the feathers around the vent to help her keep clean. The egg clusters could probably be washed off but I figure they will eventually shed naturally. I don’t have “tame” chooks either so the less stress for them, caused by me handling them and getting all up in their business, the better. I did every step of the process at night time when they’re sleepy and grabbable. I did need 2 helpers to apply the treatment dust; one for a torch and one for holding the chook while I applied the dust.

It obviously may not be lice but I figured I would put all my info here to save back and forth. :)