Hi Rich386,
Are your eggs fertile? If so there are many different options, if it were me, I'd just leave her to it, I wouldn't worry about candling at all. Let Mother Nature prevail. It's important to remember though, broody hens aren't like incubators and don't always hatch at day 21. Both my girls had babies hatch at day 24. It has a lot to do with the temp where you live and your hen. I remember checking my eggs late on day 23 thinking they were no good, but heard cheeping. So I left her as lifting her up affects humidity too. Don't stress, she will be great, and if no eggs happen to hatch and you can't hear any cheeping then buy a few day old chicks and put them under her at night and take away the eggs if no good.
She will protect her chicks like a lion, but when they are just hatched its a good idea to keep just her and the chicks together for about a week. Depends what other chooks and roosters you have and their behaviour. Just take it as it comes, make sure she is safe and has access to food and water...hope this helps...