I have read somewhere that Grouse will eat over 100 types of food and believe it...
This past weekend yielded 2-Rabbitts and 3-Grouse from my hunting group of buddies...
All Three Grouse gizzards had acorns, berries, green leafy folliage and minimal amounts of apples.
Try freshly cut/logged areas, they are very productive due to Grouse like to eat off the ground, they VERY RARELY will pick off the trees or bushes. Ground feeders mainly...
Early in the morning some Grouse will still be on "Roost" so don't forget to look up in the trees! Later in the day Grouse might be found around gravely areas/roads as they will ingest pebbles to help break their food up.
I'll post some pics within a week , or so, to show our luck so far this year...