Day 21 or 22 under a Hen, still no hatching!

I have a Barred Rock Hen "Betsy" sitting on eggs since March 12 or 13. We brought her into a box with shavings, food, water in our basement the night of the 13 to be away from our flock that includes 1 rooster and 18 other Hens (black laced wyandottes, barred rocks, brown layers).
So, from my calculations, they should have hatched yesterday and possibly today, but still nothing! Should I worry?
This is our first time so we are new at all this. I candled with a crappy flashlight on Day 6 or 7 and (compared to a fresh egg that was very clear), there were dark spots in the eggs. In the process 2 out of 15 eggs got broke. (Betsy was clutching one when I lifted her and it dropped on another egg). A few days after this, we found another egg broken in her water dish. Leaving 12 eggs left. Then about a week or so later, Betsy had rolled another one into her water dish where it got really cold. She had also pushed another egg to the side that was full of crap. I cleaned off that egg too and for the heck of it, put both back under her.
She has been pushing a few eggs out and then pulling them back under her....but still no chicks!!

 

I forgot to mention that we switched to a larger wooden box on about Day 16 or 17, that wouldn't kill the chicks would it? We were gentle in moving everything over!
Yes, I am a rookie.