I wouldn't call that a serious cut, though left untreated, it could become serious. Clean it with a saline rinse (or something similar if you don't have it) and put neosporin or bag balm on it. If you can, I would separate her into a clean kennel where you can clean up any poop so she doesn't step in it, getting her wound dirty. (If you can, put the kennel in the coop so she's not separated from her flock.) I would clean it 1-2 times a day for a few days until it improves.
Because this isn't a serious cut, I would expect it to heal up good enough to be fine with three days or so, and if you can't (or don't feel it necessary) to separate, I wouldn't be too worried about it as long as it's staying clean.
Pecking the feet is a part of the pecking order. How many perches do you have? Was she getting pecked from a lower perch or the one she was on? (For nighttime pecking issues, I just move birds around on the perches so the more pecky ones aren't bothering the lowers as much if at all.)