If it's longer than a few days I probably wouldn't try. After chicks are older than a week odds are she won't take them, but every hen is different.
An age gap of more than a week will also leave you with chicks that are strong and those that are still trying to keep up.
You can try, but watch...
Take the chicks as they hatch and brood them yourself. You can leave her the last to hatch if you want to. Otherwise she will leave the nest about 2 days after the first hatches.