To me, I seems very clear that there are many lessons that animals must be treated with kindness, certainly Judaism was the leader and the first system that recognized this. We have many examples. I grew up knowing the feed my animals before myself, the stories about a man helping a horse, not muzzling an oxen plowing a field, and even Kosher animals were killed as kindly as possible. Now, we have animal factories, where animals live a life unlike anything ever imagined in biblical days. They live horrendous lives of physical and mental abuse. It seems to me so inconsistent that such an animal could then be killed and considered kosher. It supports such a horrendous, abusive system. This very fact had driven me from much of the Jewish community, as it defies my sense of justice and humanity and flies in the face of the great beauty I see with Judaism. For feeling this, I have been insulted, but Judaism clearly led me to such a view. I felt a pride with knowing Judaism was to serve as a guiding light for the world, and this just contradicts everything for me. Please, I would appreciate a sincere, reflective thought and answer.
Physical and mental abuse of animals is wrong and not the Jewish way of treating Hashem's creation. Animals are created for the sake of man; we can work them, use their produce and even slaughter them for their meat. However, we are commanded to ease their pain and to prevent from causing extra suffering. (see Shulchan Aruch CM 272, 9) A frailer to observe these Halachic requirements has nothing to do with Kashrut. The meat will be Kosher even if the animal was abused by its Jewish or non-Jewish owner as long as it was slaughtered properly.