I use a Little Giant which is similar to the new Hovabator in design. I know many people using both versions and they never close the holes so neither have I. Just add a bowl of water in the unit and you should be fine. Two things to mention though. Be careful with the temp fluctuating, I recommend an outside thermostat for this, and the clearance is very low so be careful not to go too high with the eggs. Other than that it is a pretty good unit for 1-2 clutches at a time.