Hens are really good at disguising the fact that they are unwell. This is a natural defence – hens don’t want to appear vulnerable to predators.
Because of this diarrhoea or a discharge from her vent and soiled feathers may go unnoticed. Your hen may also stop preening and grooming and be more reluctant to move around. All of this makes a perfect storm for a fly to land on your hen and lay its eggs in the soiled feathering. This is known as fly strike.
If this is not spotted quickly the eggs will very quickly hatch and the tiny maggots will burrow into the skin.
This is a very serious situation and if not quickly addressed the hen can die.
As a first-aid measure, immediately you see any sign of maggots prepare a bowl with warm water and a bubble bath – immerse your hen and remove as many maggots as can be seen. Repeat every 2 hours, and be sure to remove all maggots. Despite removing the obvious maggots, there may well be damage to the skin and microscopic maggots that are difficult to remove. Make an appointment urgently for a vet to see her. She may need more aggressive treatment to kill off the remaining infestation and to deal with the shock.