So did not know this was possible!
A had one of my RIR hens go broody a few weeks back, (pointless, because my new roos are both too young to be effective yet) and the breeder I got my last round of chickens from brought over some fertilized faverolle eggs to let the hen sit. I thought she was nuts bringing me eggs right out of the fridge. But she insisted it was fine, and I went ahead and put them under the hen.
I'll be ****ed if they aren't hatching today. I would have never in a million years guessed you could hatch refrigerated eggs. Learn something new every day!