Yeah, we could kill them but I can't bring myself to do that. They're just beings trying to live, like we are.
I also think it's probably not going to work because they go by scent. As soon as one family is killed off, another groundhog family is going to move right into their "residence." They'll find it by scent.
My solution for our gardeners is to use a spraycalled Repel-It. It does work, but you have to be diligent. And it's inexpensive, too. Although the package says you only have to use it about once every 20-30 days, I go out every Monday and spray. And then some--I'll sometimes spray every other day.
Whatever you do, don't leave the spray bottle in your car! It will make your car smell like rotten eggs.
But above and beyond all that, we've got enough stuff to protect our plants from them. I've collected all kinds of solutions, such as wire baskets to put over the tops of plants they like. Grow stuff they don't like down low (onions, leeks, garlic, herbs, etc.) and grow things they do like high up in the air. We are doing hanging tomatoes this year for the first time, but also I have elevated beds where items like tomatoes will grow. In addition, we were able to purchase some very attractive fencing to go around some of the raised beds.
I've asked the hairstyling salons to save customers' cut hair for me. Some of them are great about doing it because they like contributing to the community garden. Leaving hair around plants bugs them and the deer.
They can totally ruin gardening if you don't have a plan, that's for sure.