Hullin, Chapter Two, Mishnah Six
Our mishnah deals with slaughtering a dying animal. This would have been a very important issue because if the animal dies without having been slaughtered it becomes a nevelah and is inedible. Slaughtering a dying animal, therefore, would have been of utmost economic importance. However, for it to be edible it must be determined that the animal died from being slaughtered and not on its own.
1) One who slaughtered a dying animal:
a) Rabban Shimon ben Gamaliel says: [the slaughtering is invalid] unless it jerked its foreleg and its hind leg.
b) Rabbi Eliezer says: it is enough if it spurted [the blood].
c) Rabbi Shimon said: even if one slaughtered [a dying animal] by night and the following morning he got up early and found the sides [of the throat] full of blood, the slaughtering is valid, for this proves that it spurted [the blood], as is Rabbi Eliezer’s measure.
d) The sages say: [the slaughtering is invalid] unless it jerked either its foreleg or its hind leg, or it moved its tail to and fro.
2) This is the test both with regard to large and small animals.
3) If a small animal stretched out its foreleg [at the end of the slaughtering] but did not withdraw it, [the slaughtering] is invalid, for this was just an indication of the expiration of its life.
4) When do these rules apply? To case of an animal which was believed to be dying.
a) But if it was believed to be sound, even though it did not show any of these signs, the slaughtering is valid.
Section one: There are basically two different opinions as to how to determine whether or not the animal died from the slaughtering or on its own. According to Rabban Shimon ben Gamaliel if the animal doesnt jerk its foreleg and hind leg when slaughtered, it is a sign that the animal was already dead. The sages in section four add that wagging its tail is also a sign that it died from slaughtering.
Rabbi Eliezer and Rabbi Shimon believe that the sign is the spurting of blood from the neck at the time of slaughtering. Rabbi Shimon adds that even if he slaughtered the dying animal at night, probably because he felt that he couldnt wait until morning, and he didnt see blood at the time of slaughtering, but the next morning he saw blood stains around the animals neck, the slaughtering was valid.
Section two: This line seems to be a continuation of the sages opinion in the previous section. The same signs that validate large animals also validate small animals.
Section three: However, if a small animal that was already dying merely stretched out its foreleg when slaughtered, this is not a sign of having died from the slaughtering. It is possible that this is just a result of dying before.
Section four: All of these signs are necessary only if the animal was known to be dying before it was slaughtered. However, if it was a healthy animal, these signs are not necessary because there is no reason to assume it died of a different cause.