I almost never bait groundhogs. The problem with using bait is domestic cats which might get curious as to whats going on, not necessarily that they'll try to eat it and if you set traps late in the afternoon/evening and the groundhog doesnt get caught first, the next morning you'll likely have a raccoon, possum or skunk instead. Fine for if you're trying to get rid of a bunch of nuisance critters from your property but I;m not there usually to catch everything, I am there to catch the groundhog(s) that are digging holes.
The way I trap them is the way I show in the pictures, put trap over the hole, fence the sides/tops as needed and done. The groundhogs must either come out of the hole if they want to eat or make another exit. I've yet to have one make another exit. I set double door cage traps, I use comstock cages. This allows for some reason if there's a groundhog or other critter outside the den when I'm setting to get caught trying to get back in. You can, and I have, used single door traps over the holes if you dont have double doors(i only do so when I run out of em) with fencing.
Only time I entertain the idea of baiting groundhogs is if I've got a place where theres no dens on the property and we have a raiding groundhog and theres no fences or trails that its using, then I'll resort to bait or the guns.
Thanks for sharing, I might just give it a try.