Missing eggs, broody chicken

[ArielRed]

After years of chicken keeping I have finally got a broody hen . . . and of course I need help. I had a raccoon attack that I thought had resulted in a flock full of dead chickens. A few weeks later I had a hen return, eat, and leave again. After a few days I followed her and found she was broody and sitting on a clutch of eggs hidden under my deck. I decided to let nature take it's course. I checked her once a day but let her eggs alone. Yesterday I noticed she had kicked an egg from the nest and I got concerned. Today when she left to do her once a day eat and drink my son saw she was sitting on just one egg now!

We took a look around and found cracked egg shells, not in the nest, but within a few feet of it. Most were just little bits of shells but there was one egg about three feet away that had a hole in the top/side and nothing inside. The hole was about half a size larger than a quarter. Do you think a predator is stealing her eggs right out from under her? Is she pushing the eggs away and something is getting them? What could it be?

I hate to force her to abandon that last egg but 'm scared a predator will take her once the eggs are gone. I do have an incubator I could toss it in but I don't even know what day we're at for hatching because I don't know exactly when she went broody. I'm not even sure if it could be fertile because of when my roo got taken.

 

[ArielRed]

Any help? I'm leaning towards putting the last egg in the incubator but I'm worried about what to set the humidity at as I don't know how far along it is.