its the milk in the cheese thats not great , but small amounts occasionally wont hurt~ I'm not sure why he is grinding his beak, hopefully someone else can chime in
Fred grinds his beak a lot. I've read that it's just contentment when the bird is relaxing. It makes sense as Fred does it when he's getting ready to nap....
Beak grinding is a very normal behavior. It is usually displayed when a bird is sleepy, relaxed or even just contentment.
Cheese in very small amounts 1 or 2 times a week is OK. Birds lack the the enzyme to digest milk products. I have know Parrots that were fed large amounts of cheese and needed surgery to have it removed from the crop and the intestines.
Beak grinding is part of digestion
we don't always hear it but all birds do it
the muscles used during beak grinding help stymilate and move the crop muscles and help digest the food
Hearing it is a good sign it means your bird is comfortable and relaxed and moving it more making the louder ( audile ) noise
Gongrats your in your way
Birds are lactose intolerant so just small amounts of anything such as cheese or yoghurts etc
other good sources of protien are chicken meat and bones
and nuts also ( just not peanuts )