Tough grouse.

[Red foreman]

My girlfreind does em up in a sir fry and they're pretty tasty that way.

 

[mmm...chicken]

You may have just overcooked the thing. There was a guy up at our camp and he deep fried strips of grouse in some kind of KFC flour. It was tasty but a bit rubbery. I've cooked mine by flash frying. (really really hot frying pan, seared it quickly and finished it off with some butter.)