ditto..loulou, got mom up on the screen now. No worries about if a hatch had started, mom sometimes helps them along by pushing the shell away from them. The parents also keep them quiet warm, the eggs are in direct contact with her brood patch and will come out warm and stay warm. Ours hatched in cold weather as well, around zero degrees and they were just fine. It just means we won't see much of them as they will keep them covered constantly so they aren't exposed to the cold air. I'm not sure if there is a 'time' limit on them, that would be a question for TPC.
The light can play tricks on us, many times I've yelled hatch ..only for it to be the underwing of the falcons feathers or the light dancing on an egg making it look like it's hatching. I saw the eggs a few minutes ago, now keep in mind I'm still on first coffee but they looked in tact to me, the other day though I thought I saw pips...so you aren't going crazy....
