HELP!!!!!OK, so we are new (first hatch in bator now), we THINK we are at day 21 on our runner duck egg incubation, we looked at pics to get an idea of what to look for in the way of sizing the air sac. It seems smaller than it should be to me,(It did yesterday too, so I dropped hum to 50 and candled for the official day 21 candle to check progress). There was a bit of receding in the air sac, but not as much as I'd like, so I dropped hum down to btwn 40-43, but after fixing the bator, candling, and wiping the eggs down a bit (i was told that may help them "sweat more" and the air sac to grow) well, I put them back in and put a thermometer on top of them (there's only 2 eggs left) and they are moving a lot... the thermometer is rocking... Idk if we are further than day 21, or if this is normal. I need to know if I should up the hum to 70 and lock down, or if this is OK and they always do this so I should leave it low for the air sac to progress further.... PLEASE HELP!!!!!