There's your issue.. at least in part. Temp should be 101.5 -102.. in still air, measured at the top of the eggs not on the floor. I actually like still air and prefer it for the hatching part.
Yes, I would probably bump the temp and give them longer, expectations being low but also knowing...
Sounds like your temperature is too low. Are you using a calibrated thermometer/hygrometer? Lets see, older little giant is that still or forced air and where are you running the temps? Still air should be about 102.
What do you mean by cold morning? Where are you running your bators at? They...