Lets go back a few 1000 years---before you and I started raising chickens----they must have gotten of the nest---to eat/drink/poop etc because they survived---LOL. Did your last hen poop all in the nest and all over the eggs??? If not she got off the nest when you were not looking. I set 150 in the last 3 years, I did not touch them---to make them get off the nest, eat, etc---they all did good. If you let her stay with the rest of the hens----she might not want to get off the nest very much because of other hens getting in her nest while she is off---but she will get off. I move all mine to a private hatching pen---the hen learns quick that there is no threat of other hens so my hens usually get off the nest at least once daily till getting close hatch time. Food and water is out of her reach so she has to get off the nest to eat etc. This allows her to stretch her legs, poop etc. "I" feel placing food next to her nest causes problems so I do Not do that-----some do---in my case with 150 broody hens I have never had one to poop in the nest----if I left food close---they will poop all over it or they will have to get off the eggs at hatching time to poop----which is not good in ""MY"" opinion. Good Luck
I'm with PD-Riverman and nchls school on this one....I've not done anywhere near 150 broodies, but I've done a few over the years, and I have never had a healthy broody not take care of herself well enough from brooding to recover.
If she doesn't do well, it isn't from brooding but from an over growth of worms or other latent health issue that caused the problem.
I think it would be an error to blame brooding in itself for any harm to the hen.
But it is like running a marathon, and the hen does need to be in good health or don't use her.
Be sure she has been seasonally wormed and is not carrying a load of body lice or mites which can drain a hen very quickly. Broodies are prone to external parasites because they are not taking as regular dust baths. It can help to sprinkle them with poultry dust throughout the brood or even use some Ivermectin.
Think power boost as well. Place Chick Saver in the water and feed the hen the higher protein chick start feed during the brood. She doesn't need the calcium. Give her high energy treats like BOSS or meal worms. Think of her as a trained athlete and treat her as such. She is a valuable member of your flock.
I offer food and water a reasonable stretch away from the hen but close enough so she can see it to entice her when she rouses.
But more than anything, I avoid over handling my hens as that causes way more problems.
Just my thoughts among the many voices here on BYC. Review it all, and then make the best decision for your flock as you can read the signs and get a sense of what will work better than anyone else.