January 7 is Christmas Day for Orthodox Christians
Bulgarian Christmas traditions involve fasting, the singing of carols, special foods like kolak, as well as other practices historically a part of the holiday celebration.
http://www.wvwnews.net/story.php?id=1870 Church for proper religious observances. Fasting during Advent, as well as a symbolic Christmas Eve meal are two examples of how the Orthodox religion and the Christmas holiday are intertwined in Bulgaria during the winter season.
Historically, fasting during the 40 days of Advent entailed abstaining from all animal products: meat, cheese, yogurt, milk, and eggs. Times have changed enough that Bulgarians may substitute abstaining from animal products to more personal fasts from other activities they enjoy. Fasting ends on Christmas day, where, after an essentially vegan Christmas Eve meal, meat returns to the table (or people resume normal daily practices).In addition, a common belief in Bulgaria is that Mary bore Christ on Christmas Eve, but only announced the birth the following day, on Christmas (which is celebrated December 25th). Folk tradition follows this belief – new mothers announce the birth of a new child to the world the day following the birth.
http://eeuropeanhistory.suite101.com/article.cfm/christmas_traditions_in_bulgaria