Not sure how a chicken can look pale?... Eggs usually hatch in 21-22 days so she shouldn't have to hang on much longer. Velvet sparrow has great info on her site or check out backyardchickens.com
I also have a broody hen, I'm amazed because she is a brown leghorn (I thought broodiness was bred out of them) I didn't think any of my hens would get broody and the rooster is only 5 months old... (hen's are 14 months) I haven't noticed any hanky panky in the coop but who knows for sure?!?!?
I'll keep my fingers crossed for your Hen! I'm sure she will be fine with a lovely brood of chicks before you know it.

Here is a link that might be useful: Velvet sparrow's site

I think what you mean is that her comb is pale and shrunken? That happens. They get kind of crazed, too. I would not worry about her. I have had a hen sitting eggs for maybe six weeks. The eggs apparently aren't fertile, and they keep going rotten and I remove them. But the other hens keep laying new eggs under her and so far I've allowed her to try to hatch something. Every once in a while she'll come sweeping out of the nest when I scatter scratch for the others. She'll race around madly, with her tail fully flayed, and then after about five minutes she pops back up into the nest. That's just how broody hens are!

Good luck, I hope your hen is more successful than mine have been this summer. (I recently got a new rooster, hopefully fertility will rise)

Here is a link that might be useful: See my new rooster, Tweedledum!

I think your hen will be fine. Right around the time the eggs hatch I have noticed the hen doesn't get up at all and doesn't want much to eat. As long as she has food and some water within reach, I wouldn't worry. Good luck with your hatch!