Pests?

Vermin like mice and rats altyhough not usually seen as attacking chickens certainly can be classified as pests that raisers must deal with-
Mites are certainly pests if you're a bird....
Snakes that eat eggs are pests to be concerned about...
Flies, that are attracted to manure are pests for those of us who do not appreciate flie and their maggot life stage ....
Sparrows and starlings are not direct predators for chickens but their presence can negatively impact the health of a flock by spreading disease as they steal food placed out for the laying hens....
All of the above can be considered pests without having them attack and kill a chicken directly.
I'm certain I've missed a whole lot of 'pests' that while not a direct and immediate threat to our birds, make raising poultry a challenge.