Jewish Law allows for a minimum of suffering on the part of animals in medical experiments designed for the purpose of benefiting and saving human lives (this would not include testing animals for cosmetics), but not disproportionate or unnecessary suffering even for benefiting humans. Admittedly, judging what is within the bounds of reasonable suffering may be a fine line. However, even the distress of animals is forbidden in other cases, such as stated in Deuteronomy 22, in which the eggs of a bird must not be taken for human need without first making sure the mother is sent away. Further, animals must be killed using the sharpest knife available, with no nicks, to inflict the least pain, or they are not deemed kosher for human consumption. Our pets must be fed before ourselves since they have less ability than we to delay their hunger drive. There are numerous other examples in both Torah and Talmud concerning the avoidance of undue physical suffering and psychological distress of animals.