It is a little disturbing to see it in the stool but it will not hurt her as long as she is not getting hairballs. Dogs can get hairballs just like cats do. If she were getting hairballs, she were regurgitate her food and vomit. The hair can also cause constipation. It sounds like it is not causing her any adverse effects at this time.
Unless she is getting it from your hairbrush, or out of the trash, it will be pretty difficult to get every strand up. Just do your best.
I am wondering if she wants more fiber in her diet? Maybe that is why she is eating the hair. You could try adding a 1/4 teaspoon of metamucil, to her food, once a day.
You can also give her veggies for treats. All veggies are safe except for garlic and onions. Those destroy red blood cells. My dogs like mini carrots and green beans. Veggies would increase her fiber intake as well.
There is a product called "laxatone." It is a paste that is used for hairball prevention.
It comes in different flavors and most pets like the taste. You could give her 1/2 an inch strip, twice a week, to help her pass the hair as well. If you give her the laxatone, twice a week, she should not get a hairball blockage.
They sell it at pet stores and online.
I hope this helps.