I soak them for a few hours in buttermilk. There is an enzyme in buttermilk that breaks down the connective tissue, and make them tender. It works on pheasant, wild turkeys, and grouse, as well. I either flour them, and fry them, or cook them low, and slow, in my smoker with apple wood chips.
Back in the hills my great uncle made shoe laces out of squirrel hide because it was so tough, he said you could't break it. But he proved himself wrong one day. He was running bullets for a little Wishom squirrel rifle, made in Newton County Arkansas, and dropped a fresh cast ball into the top of his boot, that was only half laced up. He ripped those laces out like they were made of straw.
Hungry horse