Hatching eggs 🐣🐣🐣🐣🐣

Hi all

Sorry to ask such a simple question but I wanted to know ----
If I put three eggs under a broody today and six tomorrow - generally does the hen sit until all the eggs hatch ??
At what point does she give up on any not hatched or should I remove any after say day 25 ?
And will the chicks that hatch first be ok if she is still sitting on Un hatched eggs

Thank you - xx

Eeek sassy I feel I may have been to eager !! I put three under today and putting 6 under to or tow when they arrive - she's a robust broody so I can put dynamite under her and she still sits so hoping praying this will be ok - I was just concerned that some would hatch and she wouldn't sit on the others

Fingers crossed sparkyrog thank you