I've got the incubator set up in my classroom with the temperature stabilized. I stopped collecting eggs from my coop last Saturday, so that I'd have enough eggs to hatch. Since Saturday two hens have laid 7 eggs, which I will remove from under them in the morning and take to school. So, do I start counting the 21 days tomorrow when I put them in the incubator, or from when I stopped collecting them from the coop 4 days ago?