In my country (USA) people abandon unwanted animals outdoors. A heavily domesticated (as in raised from birth with people) animal is pretty likely to die if they're left in the middle of nowhere, which this country has in abundance.

You never know, some of the pets might have a vore fetish.

Isn't it better that they go back into the food chain instead of being tossed in an cremation oven?

Less waste? They euthanize them first. I’d give them my body after I’m done with it, but it’s probably not going to be safe to eat