By the looks of that last egg, it's not going to hatch. See the big gas space in it, the white zone at the big end? The contents are probably liquid, never having been fertilized. And gas is building up inside.
I had an interesting discussion with a chicken-raising Facebook friend about whether or not to remove the bad egg. She recounted having to shampoo and blow-dry a buff Orpington hen who sat too long on a bad egg and had it explode on her. I sympathized completely, and shared my experiences shampooing and blow-drying everything from cedar waxwings to hummingbirds. Yes, I have blown-dried a hummingbird or two. Find that exact sentence anywhere in the universe, I challenge you.
I heard her point, but my cost-benefit analysis of the situation came out in favor of leaving the infertile egg in the nest. I've had 30 years of experience with infertile eggs in bluebird nests, and I've never had one explode in the short time it takes to fledge a brood. I do routinely remove them after the nestlings are two days old, but the ones I don't find simply get pushed down into the nest cup and do no harm. This, however, isn't a bluebird nest in a safe, predator-proof box. It's an open-cup nest about 2 1/2 feet off the ground in a shrub. I didn't want to touch this nest with my hands. I stuck the camera lens in through the leaves but never handled the eggs or young. I was taking a pretty big risk as it was, just approaching the nest. I didn't want to leave my scent on it and possibly attract a black rat snake or raccoon.
I could stand on the sidewalk, poke my camera in through the leaves, and grab a couple of shots without touching anything. Since we walk up and down the sidewalk all day long, my scent being there would not alert a predator. The chance to document an indigo bunting family's life from Day One was just too good to pass up. I knew I'd probably never have a chance like that again, and I took it. But I didn't want to touch that nest with my hands.