How can an egg hatch in cold weather

Although eggs contain a great deal of water, they can get colder than 32°F/0°C without freezing. However, eggs that reach 29°F will freeze, which usually causes death.

Explanation:

If they have been exposed to very cold temperatures then I would assume the embyros would be dead or never started, though if you had a way to keep the coop warm or if she went broody and stayed on the eggs (is sitting and still laying eggs so they aren't exposed to some bitter cold weather or breezes) then they hopefully would be okay.

ya the other dude is right