A rabbinic enactment forcing a butcher to slaughter an animal for any purchaser, even if the purchaser cannot afford to buy all of the meat, in order to ensure that there would be meat for people for the holidays. To aid the butchers, the sages ruled that the purchaser would acquire his meat by mere transfer of money, so that if something were to happen to the animal, the purchaser would lose his investment. Alternatively, the butcher gives the meat to someone else to claim on behalf of the purchaser: Eruvin 81b
Getting a portion of an animal slaughtered on a holiday, if one does/doesn't normally buy portions from the butcher's slaughtering: Shabbat 148b
Advice for butchers
A butcher should keep his slaughtering area bloody, to attract customers: Shabbat 75b
Rabbi Abba used to buy meat from 13 different butchers on Friday to find good meat for Shabbat, and he would bring the money to their houses and urge them to bring the meat quickly: Shabbat 119a
Abbaye and Rava ex-communicated a butcher who insulted Rav Tuvi bar Matna: Moed Katan 16a
Raveina refused to check a butcher's knife before the butcher used it to slaughter an animal for him, because he was going to purchase the meat; this was not considered "checking for his own use." Raveina told him to take the knife to Rava: Eruvin 63a
Rabbi Chiyya bar Abba telling of visiting a wealthy man in Ludkiya, who credited his wealth to his efforts as a butcher to save choice meats for Shabbat: Shabbat 119a
