Chagigah, Chapter 1, Mishnah 4. This mishnah addresses the question of which offerings may be used to fulfill the obligation of rejoicing, so that one need not necessarily bring special shalmei simchah just in order to have enough meat to eat.
"Yisrael yotzin yedei chovasan binedarim uvinedavos uvema'aser behemah" - Israelites fulfill their obligation with vow offerings, freewill offerings and the animal tithe:
Israelites, meaning Jews who are not kohanim, can fulfill their obligation to eat the meat of rejoicing by means of offerings that they are bringing in any case:
Nedarim - an offering that a person vowed to bring.
Nedavos - an animal that he actually consecrated, by saying of a particular animal: this is an offering.
Ma'aser behemah - one out of every ten animals, which must be brought as an offering. With this too, when he brings it as an offering, he can fulfill the obligation of shalmei simchah.
"VeHaKohanim bechataos uva'ashamos uvivchor uvechazeh vashok" - and the kohanim, with sin offerings, guilt offerings, the firstborn, and the breast and the thigh:
The kohanim can fulfill the mitzvah with the meat of the offerings that they are entitled to eat:
Chataos and ashamos - the sin offering and the guilt offering that Israelites bring, whose meat the kohanim have the right to eat. With these the kohanim can fulfill their obligation of rejoicing.
Bechor - the firstborn offering, which the kohen is entitled to eat; this too he may use.
Chazeh vashok - from every peace offering that an Israelite brings, he must give the kohen the breast and the thigh (the leg), and the kohen eats them. With these as well the kohen can fulfill his obligation of shalmei simchah.
"Aval lo va'ofos velo bamenachos" - but not with birds and not with meal offerings:
Bird offerings, such as the bird sin offering that is eaten by the kohen, and likewise the meal offerings, which are also eaten by the kohanim, cannot serve to fulfill the mitzvah of rejoicing. The reason is that rejoicing must specifically be with the meat of an animal, and not with grain products and not with birds.
In summary: in this mishnah we learned that one need not bring special shalmei simchah; rather, the obligation of rejoicing can be fulfilled with the meat of offerings that come to be eaten in any case: Israelites - with vow offerings, freewill offerings and the animal tithe; and the kohanim - with sin offerings, guilt offerings, the firstborn, and the breast and the thigh. Birds and meal offerings, however, do not fulfill the obligation, since rejoicing depends on the meat of an animal.