JJ, welcome. I don't know. I wouldn't give up hope yet. You could candle them...
My broodies have always known when to give up on a nest, but they've always had a few hatch first, I'm not sure what they would've done if none had hatched - probably sat there indefinitely
Have you candle them at any stage? Either way I think if it was me I'd wait until tomorrow, then if still nothing candle them.
LLsprings: as above, I would think your broody will abandon the nest shortly. If she can't feel movement in them and its been a few days since the others hatched her mothering hormones will kick in and she'll leave the remaining eggs in favor of raising the chicks she already has.
Re grit for chicks, I think they don't need it because chick crumbs are already ground up. When they start eating proper feed and treats then they need grit.
I remember my broodie teaching her chicks to eat grit last year. They kept picking up chunks of gravel and dropping them trying them for size.
Awww. She was a great mom. Hope she goes broody again this year.
As for impacted crops...no...not unless they are eating something other than chick crumb.
When I first got chickens 7 years ago (in england, not here) I got an eglu and 3 point of lay pullets. Nutmeg was so excited by her first experience of grass she ate a huge amount of long grass that balled up in her crop. She got all lethargic, stopped eating and was sleepy all the time, looked sad - you know tail down etc. We'd only had them 2 weeks. I took her to a vet who said she'd never done anything on a chicken before but that her crop was impacted and it would be kinder to put her to sleep. I signed the papers and left sobbing.
An hour later the vet rang and said she'd decided to operate after all - mainly for the experience and out of curiousity, and that Nutmeg had come around now and to come and pick her up! Anyway, she lived to a good old age in the end. But thats how I know all about crops...
Sorry about the two losses last night
Last night chick 3 took ages to zip so I stayed up to cheerlead it. I was worried it was getting stuck to the membrane, so stayed to make sure it was ok - until 3.30am

As soon as it was out chicks 1&2 went for it, pecing its feet, eyes and stuff and I coudn't bare to watch so I quickly whipped out chick 1&2.
There are 5 other pips. There were the same 5 when I went to bed. I got up an hour ago expecting zipping...but nothing
More than that chick 3 has rolled them over so I can;t even see the membrane over the pips going up and down to see if they're ok. Temp was way down this morning too.
We're just into day 22, so
for zipping soon and some more pips.
Not sure whether to sit there and fret or just go back to bed...