In Japan Xmas is celebrated differently than in the US (obviously). Christmas Eve is a bigger deal than Christmas Day. In Japan, traditionally, its more meaningful to make a gift than buy one. Then on Christmas Day is celebrated more like Valentine's Day where it is usually reserved for couples and romantic endeavors.
During the Xmas season, and really any other time, you can't find turkey anywhere in Japan. Turkeys don't naturally breed and thrive in Japan so most Japanese people haven't really tried turkey or developed a taste for it like we have. Additionally, most Japanese home are too small to have an over to accommodate an entire turkey. So finding a turkey in Japan is extremely difficult.
The popular story is that a "gaijin" walked into an Ayoama KFC in the 70's and mentioned he was having an X-mas party but couldn't find turkey anywhere. He loaded up on some deep fried meat and left the store with the idea of marketing their chicken during the X-mas time.
Whomever was manning the register at the time somehow ran it up the chain and the Japanese ad Christmas = Kentucky was born with an army of Yen behind it.
(I couldn't find the original video)