Shtika,
Actually, nowhere does it say that the chickens are supposed to go to tzedakah as pat of kapporos. Historically people would eat the chiken themselves.
Besides that you are assuming they keep the geshochtene chickens lying around. In my many years of observing kapporos where they shechita the chikens, there is also a whole group of people butchering and processing the chikens immediately and most are used that day or for yom Tov. ZD made a comment which had no bearing in reality.