I had the same question last fall. After researching I settled on letting the meat rest for a day in the fridge and then brining for another whole day before freezing. I couldn't be more happy with the results. On a scale of 1 to 10 with store bought being what everyone is used to as 10, Mine rated no less than 9 1/2.
First, if you freeze immediatly after butchering the meat is in a rigor mortis state and will stay that way when froze and then thawed. Second, store birds are injected with a brine solution with tasty results. What this does is help to tenderize the meat and retain moisture better when it is cooked and I might add tastes great too. (It also adds weight for the grocer - go figure!) It might sound like a lot of work but it is very worth it. A friend of mine froze his rock cornish right after butchering and was not pleased with the results. Brine solution: 1 gal. water/1 cup salt