How long til all eggs hatch??

[Flush2wice]

Chicken newbie here-
I have a small flock- 8 hens and a rooster. One hen got broody so I saved out eggs for 3 days til I got 12. Marked them with crayons and let her sit on them. They started hatching slowly. So far 7 healthy chicks over 4 days. She's still sitting on the other eggs and I can hear cheeping in one unhatched egg.
Shouldn't they have hatched in a shorter time period? How long should I let her sit on the others before giving up? I thought they would have hatched all at once. Any info is appreciated. Is this normal?
Thanks for comments.

 

[silkiechicken]

Over 4 days sounds like a long time. You gave her all the eggs on the same day right and didn't let some eggs get a head start? If so, they should hatch within about two days of each other. She is being very patient since many broodies get up after the second or third day and leave the rest. Just make sure there is food and water available which the mother hen and chicks can all reach.

Other than not setting the eggs the same day, only other thing I can think of is that she had too many eggs for her size so they got chilled and so rates of devlopment varied.

Welcome!

 

[Flush2wice]

She's patient and we still hope for at least 1 more chick. There's plenty of food and water and the new chicks are active and a lot of fun. I'm wondering how long to let Momma sit on the other eggs before we take them away.

 

[Flush2wice]

This is day 5- one more chick hatched in the night, three remaining eggs are in the process of hatching

The rooster is a barred rock and the hens are barred rocks, RIRs and aracaunas. The eggs were from all 3 breeds yet the chicks all look pretty much identical.
The eggs were collected over 3 days and kept in my pantry, after I got 12, I put them under her all at once. They have taken 5 days for them all to hatch.