Thought I'd let you guys know. While I was deboning the squirrels[the meat was falling off the bone], I had 1 squirrel in the bunch that was so old/tough, that I couldn't pull the meat off the bone. Those 4 pieces went to the waste basket.
For anybody that wants to know, I pressure cooked the squirrels for a little over 30 minutes at 10 lbs. of pressure.