I've heard of people feeding hatchlings to pac man frogs, but they were always snakes that died on their own or were going to die (bad kinks, etc).

As to the morality I don't think there's a problem with it. I bet a lot of people do but it might be just because we like snakes. It's probably the same as all the people that think we're monsters for feeding mice and rats to our snakes.

I'd be more surprised if someone was feeding morphs or female normals off, just because those still have value and enough demand to be able to get rid of them, even if it's for next to nothing. But I can just see the males being so hard to sell that you might feed them off if something can eat it.