Ohmygosh-- I had some quail in the hatcher the other day, and by the time 10 hatched in less than 12 hours, they were BOWLING and playing HOCKEY with the other eggs! I HAD to take them out! and the "lively popcorn" is darned hard to catch coming out of my styrofoam hatcher, so I have to put the hatcher in the bathtub (block the drain!) when I'm trying to get them out, or they leap out onto the floor and run around! Very nerve wracking... In the tub, I can get them out and caught quickly enough that I don't lose temp or humidity in the hatcher. The only 3 eggs that didn't hatch look to be non-fertile.
Of course, you have to use your own best judgment as to how it will affect the ones left in your hatcher, but these guys were getting DESTRUCTIVE! They were running around pecking on other eggs and stuff...they rolled one chick's egg over onto where he was zipping...and he didn't make it. Don't know if they suffocated him or what.