Tosefta for Chullin 110:29

A charuta by the hand of Heaven (i.e., without human agency) is valid. What does "charuta" mean? Any [animal whose] lung is shriveled. There are among the [potentially disqualifying defects in] limbs those that are valid: An animal with a dangling limb where there remains a sufficient quantity of [attached matter] to permit healing; an animal with dangling flesh where there remains a sufficient quantity of [attached matter] to permit healing; a broken bone that juts out and the hide and flesh [around it] are sufficient to encircle it is valid. There are among the fetuses that are valid, a five-month fetus in small animals, and a nine-month fetus in large animals. [If a fetus] had five eyes or three legs, since it is [nonetheless] similar to one that is qualified [for slaughter], it remains valid.