I'm certainly not advocating taking animals under false pretenses, but the reason people feed rodents to snakes is not because rodents are in some way less worthy of life than dogs - it's because their reproductive rate is such that they present an inexpensive and readily available food source. We even feed them to animals that normally prefer other prey. If dogs could be produced on a similar budget, I wouldn't be surprised to see them looked at differently. Heck, we might even eat them ourselves - several Asian cultures do, after all.