Considering where you live, those are probably baby cottontails. Cottontail mothers don't dig a burrow, their nests are usually little more than bowl-shaped scrapes on the surface with a little bit of fur for warmth and some grass and/or leaves as cover. The doe only comes to feed her kits around dawn and dusk, otherwise, she stays away from them. I'd be willing to bet that those babies' mom is sitting in deep cover less than a hundred feet from where they were found.
Putting a nest in a yard where there is a dog seems pretty crazy, but there are predators everywhere in the wild. A rabbit once nested in the back yard where we had 5 dogs, and nearly succeeded, too; the kits had their eyes open when one of my dogs finally found them. Sadly, the dog was an experienced ratter and was very fast, and killed 3 before we got to her. I had to finish raising the last one; the dog wouldn't leave the nest alone once discovered. There was another situation where I wound up taking in a litter when a nest site was disturbed past recognition, there were 4 in that litter, too.
Legally speaking, the only people who are supposed to do this sort of thing are licensed wildlife rehabilitators, if you can find one to get them to, great! If not, these are the things that I did:
KMR (Kitten Milk Replacer) - a few cc's at a time. I fed with an eyedropper at first, until they got the idea. You have to be very, very careful not to get it in the nose, as breathing it in can cause aspiration pneumonia. Once they get the idea, you can use a kitten-sized bottle (pet shops often have them, in the same area as the KMR). I only fed them 2 -3 times a day, since wild things are so stressed by being handled. KMR is not as nutrient-dense as rabbit milk, but I figured they were better off growing slowly due to lack of nutrition than dealing with all that stress!
I bedded the kits in hay; once they had their eyes open, they started nibbling on it. I also provided dry rolled oats (like you make oatmeal with) for them to nibble at that age, too.
Obviously, rabbit food pellets aren't natural wild food, so I only added it to the diet because I had it on hand. I provided lots of fresh green grass and other wild foods like blackberry leaves. The cage they were in had a wire floor, so I set it out in shady parts of the yard so the bunnies could "graze."
Wild rabbit kits wean and disperse at a pretty young age. They really aren't social at all. If you wind up raising these kits, you will need to release them when they are about a month to 6 weeks old. Any older than that, and they will begin fighting with each other. Wild rabbits really don't make good pets, because most of them never really get over being wild. I didn't even try to tame the ones I had, it was in my mind all along that they would be released as soon as I felt they could fend for themselves.
