There has been some good advice said already, my hunting camp has shot quite a few grouse and here are our conclusions.
1) The grouse that I hunt are ruffed and blue. Obviously there is a big difference between the two in size, a big blue grouse is one tough critter.
2) Grouse heads/necks are small targets. The neck is about as big around as your pinky finger and the head moves quite a bit. If you are a good shot or don't mind missing quite abit head shots are fine. But if your hunting camp rations are down to canned veggies and some pickles you might find a body shot with a bit of meat damage acceptable.
3) No field points. It is nice that they are cheap and fly straight, but that is about it as for benefits. I will never, ever shoot another animal of any kind with a field point.
4) Judos are not good for body shots. Blue grouse can be hit with a judo point in the chest with a 65lb. bow and fly away with the arrow (true story) and if the animal is retrieved the judo makes a mess of the breast meat.
My prefrence is to use old, damaged broadheads for any small game animal. Do not cry if you accidentaly hit a grouse in the breast. As unfortunate as this is it can be saved as long as you clean it immediatly and gently rinse it off, blood in the meat does not taste bad.
Have fun, there is nothing more fun than chasing grouse!