I hate killing, yet I have a lot of friends who take gardening very seriously - some are completely self-sufficient! Is is a bad thing to kill the pests which ruin their crops? If they do not kill the pests, then the pests multiply and ruin the harvest. Any advice?

it depends, if it is one of those places that doesnt have very many of the rodents than YES ((its a bad thing)) def. but if it one of those states or counties that have way too many than its slightly less of a big deal. But as for me, i woudnt do it to save my life. I hope that helps.

kill the bastards, if you feel bad about it, toss them into the compost pile.