Well, chickens tend to live off insects when you let them roam.
I don't really see how insect powder would be worse than the flour they get now. You don't even need to turn the bugs into a powder.
Indeed we already feed them insects and we don't powder them. You can purchase bags of dried meal worms at the feed store. The carcasses are fully intact.
To be fair, chickens can see and discriminate between insects before putting them in their mouths. Powdered insects preclude that.
Likewise, cows would never eat a carcass cow, but as hamburger mixed with a lot of grass...