For the last three days my larger 5 week old chicks (all seemingly of the same breed) have poo sticking to their bottoms. There are 14 of these with the same problem and they are the larger chicks in the group. It looks like their feathers are either not yet in, or have been picked out on their bums and under their wings. The smaller chicks are fine - no similar issues. I have been washing them off, but the problem persists. Is it chiggers? Lice? Something more dire? My local extension office said "I don't know anything about chickens." Very helpful.