Eggs abandoned by broody

Hi - Does anyone know how long an egg can last if the broody no longer will sit on them? My Pekin duck has been sitting for over 2 wks on her nest. I candled all 12 and all 12 were forming. We had a storm come in a couple of days ago, and even though she is in the nest box inside the chicken house, she left her nest with the other 4 ducks and has not gone back to her eggs. Its been 2 days now. I pulled two and cracked them open to see if they were bad or whatever. Both were developing little ducks, one even had its feathers already. Neither showed signs of life and were very cold. Theres 8 eggs left in the nest. If these were put into an incubator or under one of my broody hens (2 are sitting on one nest) is it too late for these duck eggs to survive now? Thanks for any info.

 

We had to leave on a small vac. we had scheduled. During that time one of the broody hens moved over to that nest and she has been sitting on it ever since. She gets real nasty if I try to reach under her but I'd like to see what's up with the eggs. They were cold for 3 days (temp. in the 50's at night, 60's during day). I did open a couple of eggs after the duck left them and I know there are different stages of development going on as the ducks crawl over ea. other and cont. laying in the nest prior to this. One egg was developed probably a couple of wk old (bald, buggy eggs, very small), the other one was pretty developed (brn & wh. feathers, pretty well developed - made me really sad) Both of those were not showing any signs of life (wiggling, or anything). The 6-8 left in there I have no idea what stages they are at. Can you see ducks move within the egg when you candle if they are alive? Thanks