If you age a squirrel in air for 4 days without the skin on you will have squirrel jerky. Belive me I have tried it. Putting the squirrel in water in the fridge will keep you from losing any moisture from the squirrel. Also allowing the squirrel to age in the fridge will tenderize the toughest of squirrels. It works the same way as adging big game. I almost use the same process with big game except I age quarterd big game in the fridge in a plastic tub with a 30 gallon garbage bag covering the meat to keep the meat from losing any moisture.Its not pretty but it works well. I never worry about the age of the animal I shoot.I have never tried brining . But I guarntee you this will tenderize the toughest game.
Way down yonder in the land of cotton...