Tosefta על חולין 75:50

Rabbi Shimon says in the name of Rabbi Eliezer, one who slaughters at night, and at daybreak he came and found walls full of blood, [the slaughter is] valid (Hul. 2:6) since he knows that [the blood] spurted. Rabbi Yosei says, Rabbi Meir would say, if it lowed at the time of slaughter, it is valid (Hul. 38a:5). Rabbi Eliezer son of Rabbi Yosei says in his name, [if he slaughters an animal whose] eyes are trembling, or if he finds excrement at the time of slaughter, [the slaughter is] valid. If it straightened its foreleg and did not bring it back, it is invalid, as there is nothing but [evidence of] the expiring of a life. And [as to] the hindleg, [if the animal] straightens the leg and does not bring it back, or brings the leg back but does not straighten it, the slaughter is valid (see Hul. 2:6, Hul. 38a:3). To what case does this rule apply? To a small animal, but as to a large animal, whether the foreleg or the hindleg, [whether] it straightens but does not bring it back or brings it back but does not straighten, [the slaughter] is valid. To what case does this rule apply? To livestock but as to fowl, even if it only twitched the top of its wing or the top of its tail, [the slaughter is] valid.