That’s really lousy news. That sounds like a skunk, rat, or possum but I’m not sure. It could be many things. Since it was daylight after dawn I’d lean toward a skunk. Was there any smell? Often you can get the skunk smell just from them having been in the area. They may have gotten broken by her trying to fight something off.
Another possibility is that she was fighting another hen that tried to lay in there with her. I’ve had two broodies fight over the eggs and about half the eggs were destroyed. That stuff doesn’t happen often but it does happen. That’s the only time I’ve ever had a problem with another hen. I have had a snake eat eggs out from under a broody but those eggs just disappeared.
I’d certainly try to move her again. If something is getting into her nest, she won’t be able to hatch before the eggs are eaten or destroyed. That happened with the snake. I had to hatch in an incubator and give her the chicks.
If the eggs are dirty I’d start with fresh ones. The eggs with that egg goo on them can easily get bacteria inside and go rotten. I wouldn’t take that chance.
If it was her fighting another hen you may never know what happened. If it was a predator of some sort, you need to try to figure out what you have and deal with it. It will be back. If you have a live trap sized for a raccoon, I suggest baiting it with peanut butter. Just wad some up in a paper towel and toss that back behind the trip lever. Peanut butter is pretty much a universal bait. Another suggestion is to try to get some tracks so you can identify it. Smooth out some dirt where it is likely to walk or even spread some flour to help get prints.