i learned this from an elderly friend of mine from england who has been an avid bird hunter since about 54BC. on our first pheasant hunt he took the birds and hung them outside on his barn for about a week. no refridgeration, no ice, just dead and hanging. i was a guest so i kept my mouth shut and went with the flow.
after a week, you dress them as you would and cook them. we may have beaten them in a war but they know how to prepare pheasant !
from what i understand, the time they hang allows provides for some chemistry changes and decomposition not unlike a meat tenderizer. he said he was taught this way of preparing birds because, as a kid during WWII, they had no refridgeration due to power outages brought on by war activities. as a side note, he also said that during the war, the english "invented" steak sauce, like Lea & Perrins, to mask the odor of less than fresh meats and poultry !
i have served birds this way and never had a complaint of bad taste nor lost a guest to food poisoning !
sg