general goose hatching question

This year for me was the "Year of the Incubator". I have had weekly hatched of ducks, geese and sometimes chickens since March 15th. Our ducks and chickens have been incredibly fertile. I'm hatching only around 50% on the geese, but from what I have read I could be doing worse.

So, here is my question. I was cleaning out the hatching tray a full week after my last hatch. There was a gosling in there. He/She apparently came 6 days later than the rest of them. I regularly get goslings 2-3 days after the first one comes out. So, knowing the hatches are often spread out over 3-4 days, how do commercial hatcheries ship "day old" goslings reliably? It must be just crazy for them trying to get the hatches on the right day to ship on the correct day.

Who knows the industry and can take a stab at the answer?