From the word in the beginning,
it was not so.
According to Genesis, in the very beginning every creature was vegetarian. I think it was to Noah that God gave permission to kill animals for food.

And the commandment not to kill doesn't make any exceptions.
Can't we even swat mosquitoes? Are lions going to hell because they break the commandment not to kill?

When man lays down his rebelleous spirit,
the lion shall lay down with the lamb
That's figurative language to prophesy that enemies will learn to trust each other and eventually to love each other and stop being enemies.

Radar