Queen bees go from egg laying day to hatched in about 16 days. If the bees started making queen cells on 9/1, the queens would be made from larvae on day 4 of the cycle. The queens would hatch out on about the 12th.
Keep in mind the Queen hatches 16 days from the day the EGG is LAID.I pulled the queen and three frames of bees from a double deep colony late in the afternoon on September 1 to get some Queens raised for splits. I inspected the queenless colony a few days ago and found about a dozen healthy looking capped Queen cells. It's been raining a lot here and finding enough time to get bee work done between showers has been difficult. I got cut short because of weather during the inspection and quickly broke the double deep up into four nucs (15 frames full of bees, 90% fully drawn with mixed stores and brood) with plans to go back and cut out individual Queen cells for more splits. For whatever reason, I didn't put a frame with a queen cell in one of the four nucs.
I had to work Sunday so I planned to cut Queen cells out yesterday and make up a few more nucs but it rained all day and was forecast to be much drier today so I thought to wait until today, the 15th thinking I had another day or two until the Queen's hatched. Wrong.
Got into the four nucs today and they had all hatched, and one of the nucs with cap Queen cells had been robbed out, leaving only two with potential Queens. I had enough bees and queen cells to get possibly nine nucs made up, got two instead. Isn't that a day or two early? Queen pulled on September 1st, new Queen's hatch on September 15th.