I think ANY dust can be dangerous to breathe. Not good for the lungs. I wear a respirator - not a dust mask but the good kind that has been fitted to my face - whenever I clean the coop or add DE. But in a well ventilated area for short periods of time I don't worry about the dust. Generally speaking if I can see dust in the air, sense the dust in my nose or feel any irritation in the eyes or nose I use the mask.
I think if chickens are sick or in a very dirty coop (ammonia smell) there could be other hazards to your health but that isn't (shouldn't be) typical. I did read on BYC about a woman who claimed to get sick from cleaning the chicken coop and inhaling something (bacteria I think) but I don't know what it was or if the claim is true, I know she said she was treated and was fine and now wears a mask.
I think if chickens are sick or in a very dirty coop (ammonia smell) there could be other hazards to your health but that isn't (shouldn't be) typical. I did read on BYC about a woman who claimed to get sick from cleaning the chicken coop and inhaling something (bacteria I think) but I don't know what it was or if the claim is true, I know she said she was treated and was fine and now wears a mask.
