The advice hub Lice
Chickens can also suffer from Lice (Menophon gallinae) which are golden in colour and approximately 1-3mm in length. These lice are fast moving, laying their white eggs (nits) around the vent, base of feathers and under the wings.
This burrowing causes damage to the tissue which oozes with a nutrient rich fluid on which the depluming mites feed. This burrowing causes irritation and pain to the chicken causing it to scratch and to pull out its own feathers. Severely burdened chickens will lose weight and will lay fewer eggs.
The lice bite the chicken and feed from its skin and also the fluid which oozes from the damaged skin. Low levels of lice only cause mild irritation but large numbers lead to weight loss, restlessness and a reduction egg production. They tend to rapidly increase in number around the autumn and winter. Lice only live a few days and are often transmitted by direct contact.
The best way to treat them is to use a combination of Ivermectin 1% drops and Diatomaceous Earth, as previously described. Treat the house as you would for red mite infestation.