The attitude toward animal life differs from the attitude toward human life. Because human beings were created in the image of God, endowed with a living soul, and entrusted with responsibility for perfecting the world, human life has sanctity. Every moment of human life, while the divine soul rests within the body, is more precious than gold. Under no circumstances may a person’s life be shortened, even to end the suffering caused by severe illness. Animal life, however, does not have that same sanctity. The mitzva is to avoid causing animals to suffer, but there is no mitzva to preserve their lives. Accordingly, if a cat or dog under a person’s care is suffering from a terminal illness or from injuries sustained in an accident, and it is in pain with no chance of recovery, it is preferable to have it put down painlessly in order to spare it suffering.
Moreover, animal-welfare organizations that are left with dogs or cats no one is willing to adopt may have them put down painlessly. Similarly, if caring for a dog has become too difficult and the dog is suffering as a result, and no one else is willing to take it, the owner may put it down painlessly (Maharshal, Bava Kamma 10:37). We have learned that the Sages warned a person not to bring an animal into his domain unless he knows that he will be able to feed it properly (Yerushalmi, Ketubot 4:8). But this warning applies before he takes responsibility for the animal; it does not make him enslaved to the animal for the rest of its life. If he took in the animal thinking he would be able to support it, but later realized that doing so is too difficult, he may put it down in order to spare it suffering, so that it will not die of starvation.
At times there is an economic necessity to kill animals. For example, the owner of a fishpond must market the fish at certain times, according to market demand. If the fish mature too early or too late, he may be left with a pond full of fish and no market for them. Ideally, of course, he should look for a way to sell the fish and not dispose of them unnecessarily. But if no solution is found, the owner is not obligated to continue spending money to feed them, and he may kill them.
The same applies to chicks and chickens that have no market value, when the cost of raising them would exceed whatever breeders could earn from selling them. In such cases, breeders may kill them, since they are not obligated to feed animals from which they will derive no financial benefit (see above, 13:8).[5]
