This confuses me. Why, first of all, would you give her something to sit on if you weren't going to let her hatch or take the chicks before hatch to raise, and why would you /not/ candle before hand, even if you thought they were all rotten?I once placed a (different breed) bantam egg under my MGB that was trying to go broody, just so she had something to sit on for a while. Every night I took her off and put her in her roost to keep her safe. On about day 10 of this I decided to crack the rotten eggs incase they exploded...
This one I watched hit the tree, only to see red show between the cracked shell. It was a chick; and it was alive! It was moving. It had feathers.
If I remember correctly it got down to about 17C at night, or a bit less. I was amazed that it survived so long getting so cold every night!
I wished I would have candled it first - but who would have thought...?