We understand about the innocence of animals, and that they don't deserve to suffer, and we've been pondering the same questions, too. However, do to some spiritual laws God set into motion when He created the heavens and the earth, the animals are tied to humans.
If humans had obeyed God, we'd be still living in Eden, and when we turn back to God, we will again have a peaceable kingdom like the one Isaiah describes in 11:6-9.
We were created in God's image, but we are no longer living in His image. Our disobedience and sin separated us from God, and Jesus tried to being us back, but relatively few have answered His call. Most people choose to live in the sins of the world, and we and the animals suffer for it.
Does this answer your question?
In the Love of the Lord,
Frank and Mary