How long exactly do European eggs take to hatch?

[Curiosity]

I'm asking because I have four eggs that have been just sitting on the bookshelf for more than a month now. I pulled them out of the fridge in mid November. Two of them I didn't expect to hatch anyway, but the two I was actually hopeful about show no obvious signs of life either. I don't think I let them get dried out, although there have been several days where I realized I hadn't misted the eggs in a couple of days. 

 

[MrGhostMantis]

Are you keeping them warm after them being out of the fridge?

 

[Curiosity]

@MrGhostMantis They're at the same temperature as the rest of the room. The thermostat in the room is set for 70 degrees Fahrenheit. Is that not warm enough?

 

[MrGhostMantis]

Maybe warm it up a bit.

 

[Curiosity]

Okay thanks

 

[Curiosity]

One of them just hatched.