Hello- I have read several posts concerning use of egg cartons for last days of hatch. We have recently hatched several full batches of guinea eggs in a hovabator and got tired of the time required to turn 50+ eggs. We have now hatched three batches using egg cartons for the full incubation period. A hovabator will hold 5 egg cartons. We placed a rubber band around the cartons and placed in incubator with cartons at a 45 angle. Turning now takes a matter of seconds since we now can rotate the entire carton 180 degrees. On day 25 we cut the tops off the cartons and lay them flat. I thought I would share this as it seems to have worked well. The only problems we have had is that twice the eggs have hatched early before we cut the tops off. But we have used cardboard cartons with holes in top so we found keets with their heads sticking throught the holes on morning we thought we were ready to stop turning. It also makes it easier to keep the eggs organized during candling. I should mention we have added fans to our hovabators which really seemed to even out and improve the hatch rate. The last batch of 18 started hatching this morning on day 25, which is really early. We checked and rechecked our math. Incubation temps were the same. Same parent birds. So we don't know why so early, but the keets look good and as of now all but two have hatched or pipped. We haven't tried this yet on chicken eggs. On a different issue, we stopped using tap water (well water) in the humidity tray and switched to sanitized (Oxine-15 drops per gallon) drinking water. The incubator seems to smell a lot less at the end of the hatch. Any suggestions or thoughts?