It's important to remember that the animals are not grieving with us. They're very accepting. They're not lying there thinking 'How could you do this to me? Why aren't you keeping me going?' Pets don't do the human things of guilt and anger and recrimination that we do. They come and go with great acceptance.
Animals have come to mean so much in our lives. We live in a fragmented and disconnected culture. Politics are ugly, religion is struggling, technology is stressful, and the economy is unfortunate. What's one thing that we have in our lives that we can depend on? A dog or a cat loving us unconditionally, every day, very faithfully.
I am no theologian, and do not have the answers to these questions, and one of the reasons I enjoy the animals on the farm so much is that they don't think about their pain, or question it, they accept it and endure it, true stoics. I have never heard a donkey or cow whine (although I guess dogs do). I told my friend this: pain, like joy, is a gift. It challenges us, tests, defines us, causes us to grow, empathize, and also, to appreciate its absence. If nothing else, it sharpens the experience of joy. The minute something happens to me that causes pain, I start wondering how I can respond to it, what I can learn from it, what it has taught me or shown me about myself. This doesn't make it hurt any less, but it puts it, for me, on a more manageable level. I don't know if there is a God, or if he causes me or anybody else to hurt, or if he could stop pain. I try to accept it and live beyond it. I think the animals have taught me that. The Problem of Pain is that it exists, and is ubiquitous. The Challenge of Pain is how we respond to it.
I think if I've learned anything about friendship, it's to hang in, stay connected, fight for them, and let them fight for you. Don't walk away, don't be distracted, don't be too busy or tired, don't take them for granted. Friends are part of the glue that holds life and faith together. Powerful stuff.