If it's ok to...

[Matt K]

Why use a word other than euthanize?
It wouldnt be to add ambiguity to the act, would it?
Which is why of course they used it in the kids novel...

The word 'cull' is used in the natural sciences, and is a more appropriate word to use in this case, as it carries with it connotations of removing an animal from a gene pool based on undesirable genetic traits or defects. Like euthanasia, culling almost always implies putting the animal down as a means of doing so. It doesn't add ambiguity at all, in fact, it gives us additional information.

Cheers,
-Matt