Winchester WinLite or Remington managed recoil STS target loads are options you can probably find locally. My local WalMart often has the STS.
For whatever reason, grouse are very easy to bring down. Any 20 ga load will put an end to a grouse. I find STS 28 ga target loads kill blue grouse just fine (and blues are a good bit bigger than ruffed).
Before she grew old, deaf, and senile, my silly dog would get a bit flustered when someone shot over her. So, I picked loads speifically for minimum noise. She got over it but I stayed with the light stuff because it kills them fine and as a bonus doesn't damage the the meat as much.
Good luck!
