Tosefta על חולין 122:22

One who slaughters [an animal intended for] a burnt offering [with the intention] to sprinkle its blood outside (i.e., outside the Temple), or some of the blood outside, to eat its flesh outside, or an olive's bulk of its flesh outside: It is disqualified, but they may not hold [the priest] liable for excision, and you can say the same as to uncircumcised and impure [priests]. One who slaughters a sacrificial animal [with the intention] to eat an olive's bulk of the skin of the fatty tail outside its designated area: It is disqualified, but [the priest] is not liable for excision. [But if he intended to burn it] beyond its designated time, it is piggul, and they hold him liable for excision. Rabbi Elazar ben Yehuda of Aveilum (not "Ochlin"; see Hul. 122b:7) said in the name of Rabbi Yaakov, and so too would Rabbi Shimon ben Yehuda of K'far 'Ikkom say in the name of Rabbi Shimon: The same law applies to the skin of the fatty tail and the skin of the head and the skin [covering] the hooves.