It is. Osha Class 3, Generally Regarded As Safe if used within minimum exposure.
But, unfortunately, it's not good for you or especially your birds to breath. The continuous breathing of fine dust in birds causes scar tissue in the bronchial junction, leading to increased difficulty breathing, respiratory distress and suffocation.
It's barely mediocre for mite and lice control and it's harvesting by strip, i.e open pit mining, which is not environmentally friendly. So, unfortunately, it's not safe, effective or good for the planet.