It may have been because I was moving a new villager in and I had put the eggs in the plaza from my main character. I reset the time back to 5:58 this morning because I didn't want to miss bunny day and came in on my secondary character to ensure there were no Nook refugees. When I had finished and saved and went on my main character the eggs were no longer there.

I'm glad to know that we can put eggs on the ground. I was pretty disappointed.