My lot caught lice from the chickens 3 years ago.. I treated everything and everyone then full clipped the lot of them in March to be sure there were none left I'd missed..
Sounds like treatment is all in hand and they want to explain why he is looking a bit ratty so people don't call the RSPCA/aren't too put off.
Lice happen sometimes, mine had lice when I got her. No big deal though and easily got rid of. Youngsters have perfect coats for harbouring the little blighters