: In poultry like chickens, a bad infestation can lead to a drop in egg production and weight loss. Can They Affect Humans? Lice of Poultry - MSD Veterinary Manual
While a few lice are normal for most wild birds, heavy infestations can cause significant distress: bird louse
: Irritation from the lice crawling and chewing can lead to skin damage. : In poultry like chickens, a bad infestation
: Excessive feeding can leave feathers looking tattered or "moth-eaten". : In poultry like chickens