I used to have a conure who loved it, so when we got chickens, I did it all the time! Some like it more than others, but if you gently "pop" the casings that are dry between your thumb and forefinger, then roll them a little between your fingers, they just flake right off. My OEGB LOVES it!
Willow
I've always popped the feather casings on my guys. Also on my conure. They all seem to really like it and close their eyes while I preen them. Then they stand up, shake off the casing dust and get fluffy!
Willow