Day old chicks and broody hen advice please

[chickenchick123]

Hi, Any advice on when to pop day old chicks under my broody hen please? She's been broody for a week and is settled in a separate coop from the rest of the flock.

Last year I had a broody hatch out fertile eggs, but I don't want any chance of roosters this year, so i will get sexed chicks from my local farm.

The eggs she's sitting on are fertile from our rooster so I don't really want to leave her too long on them. Do I need to wait 3 weeks or might I get away with letting her brood for less, I feel bad about the eggs she sat on, I don't want them to develop.
Any advice would be great thanks.

Also I have a bag of unopened chick starter from last year left,does it go out of date of should i just buy new?!

Thanks in advance x

 

[chickenchick123]

Any advice please?
I'm going to the farm today to see when their incubated chicks will arrive. Unfortunately my local farm owner is grumpy and unwilling to offer very much advice at all. I'm not really sure where another farm is and we don't have pet shops who sell anything more than rodents and fish here in the uk either. I was hoping for some helpful advice on here!?