My peahens used to leave eggs laying randomly around the yard. They were young, and some one told me peahens were really stupid mothers and couldn't be trusted to raise their young. Dopey me- I listened to them and would pick up the eggs. Well, years later, I was told by an old-timer that peahens are really smart- and those random eggs are decoys to see if the area is safe to nest- or if predators are waiting for the eggs....Now, I don't know if that"s a wives tale or not- after all, my hens were young, but i now try not to disturb those decoy eggs- unless they are actualy under foot, and my hens have since been successful nesters. Again, they matured, but also the decoy eggs were never included in their nest. So, my suggestion,( and I am not nearly as experienced as most on this site) is assume that egg is infertile, but leave it be if you can- and see if she's just testing the territory.
Well i already opened it and I think it was fertile but I think she will nest there if I find another one I'll leave it alone