You ask a good question. What is the source of evil? The famed Jewish sage, Moses Maimonides was of the opinion that G-d does not cause evil. G-d only does good. Thus, evil is the result of one of three things. Three events cause harm. People harm themselves, harm others, and natural law, which is good for the world as a whole but may harm individuals. For example, a hurricane cleans the earth but may kill people. SoHowever, it would seem as if your addressing question would fall under the third category (since most harm done to animalsnature is not of the result of humans)really evil. Humans perceive it as such because they are too self-centered. In contrast to human suffering, the Rambam writes that most suffering is self-inflicting.
When Isaiah described lions lying with sheep and beating swords into plowshares, these were parables (Maimonides). The Rambam writes that he was speaking figuratively about an ideal society. Interestingly, but to the surprise of many, Rambam did not think the laws of nature will change in the messianic age. Rather, Jews will have political freedom.[1]
From this view, we see that Maimonides showed much compassion for animals. He correctly understood that animals, like humans, have emotions and can feel pain. He interpretedFor example, Maimonides says that the commands of Deuteronomy 22:6 commands: “If you chance upon a bird’s nest along the road, in any tree or on the ground, with fledglings or eggs, and the mother is sitting over the fledglings or the eggs, do not take the mother together with her young.” Leviticus 22:28 is similar: “No animal from the herd or from the flock should be slaughtered on the same day with its young.” Maimonides says that these commands recognize that animals have feelings and that people should respect animals, for they also have feelings.
Similarly, the Seven Laws of Noah prohibits eating flesh from a live animal. People should respect animals, for they also have feelings. We should even be cautious when we walkwalking as not to trend on ants. This is why a person does not take the eggs from a bird’s nest if the mother bird is near, for the mother [if not chased] can not bear to see her chicks taken before her. This is why people should chase the bird away. It may even prompt the person to feel sorry for the chicks and leave the eggs alone. We see from here that it is prohibited for people to torment animals.[3]
It is worth noting here that originally humans were vegetarians (Genesis 2:16). It's only later thatafter Noah's flood when the Torah gives permission (a concession) to eat meat (Genesis 9:3). It seems that the Torah prefers a vegetarian meal, but recognizing human desires, allowed people (for example, Noah) to be carnivorous.
Maimonides disagreed. He felt that it is not ”through the interference of divine providence that a certain leaf falls [from a tree], nor do I hold that when a certain spider catches a certain fly, that this is the direct result of a special decree and will of G-d due that moment… In all these cases the action is, according to my opinion, entirely due to chance, as taught by Aristotle…"
It seems as though Nachmainides did not believe there arewere laws of nature. Maimonides, in contrast, believed that there were laws of nature that govern the universe. Leaves falling, in general, is G-d's plan (we might call this gravity). I accept the latter view because it fits well with science. Since G-d is perfect, this must be the best of all possible worlds. Since G-d is perfect, everything is "good" and could not be other than what it is. Indeed, the Bible says that G-d created the world "Very good." It implies that G-d is not like a plumber, who needs to return on a daily bases to modify His creations because it is in a state of flux.