Dogs are predators though, I think what you're talking about applies to herd animals that are prey, predators will pick off the weakest.
I always thought that pack animals abandoned their sick or injured to not slow down the rest of the pack which is why dogs hide injuries. But apparently wolves protect their injured.
Do you know how many times I install and uninstall a game before I even play it? I could probably destroy a small game company on my own with this fee structure, and I'm sure I'm not alone with the constant installing and uninstalling.