This was about four years ago, but it still annoys the hell out of me. My behind-the-wheel driving instructor told us we must obey the "thump-thump" rule. That is, never try to avoid an animal in the road because it braking or swerving can be extremely dangerous.
I understand that you don't want to swerve to avoid an animal when you're going down the highway and are surrounded by other vehicles. But if I have a safe chance to brake or avoid it, then I most certainly will. It'd be cruel not to.