The sister site "Backyardchickenforum" has alot of information on this topic, and is a great resource for info from elders.Due to a lack of info on broody hen behavior and the how to / what to do's on natural egg hatching I went searching this morning for info. I found 2 nice articles on it and really wish I had found them sooner, but, here I am on day 11 of my broody hens setting on eggs.
I liked this detailed write up by The Chicken Chick
https://the-chicken-chick.com/caring-for-broody-hens-facilitating-egg/#:~:text=WHAT IS A BROODY HEN,or less) until they hatch
This one was good to,
https://www.fresheggsdaily.blog/2013/05/annie-and-her-chicks-hatching-eggs.html
Since I am striving to be a Sufficient Self, For me, I don't want to depend on electric incubators or hatcheries to supply a flock.
In the past, many years ago, I had a hen that sat on a few eggs and when they hatched- she attacked them, so I went and got her some already hatched chicks from a local farm store, it went fine. She raised them up.
Now, this is my second attempt at letting a hen hatch eggs.
I think new homesteaders and even we that have been at it for many years still have much to learn.
The elders should share / write down/ teach knowledge
I just hatched my own first batch this year, for similar reasons to you. It went well, 11 of 13 hatched, but an unpredicted cold snap from 70 to -20 that night killed 2. The others she raised to adulthood, along with another 19 from an incubator a week apart! In my research I have found that the breed of chicken is pretty important (mine is red dorking) but beyond that sometimes you just don't know, they each have their own personalities and quarks. Im sorry to hear she attacked them, that must have been hard. Was she a pullet? I have heard of pullets doing odd things like that.
Having the broody in a cordoned off area safe from the rest of the flock and predators, with her own food, water, and dust bath is very helpful. Some people (me included) put the chicken acting broody in a place set aside for that with a particularly large and luxurious nesting box before they let her start setting. (I used a small "dogloo") some people also regularly check on her and bring food and water actively to her (I did) while others say to leave her alone. Some people say to give her scrambled eggs every once in a while, especially after week 2 (I did that as well). There is also some debate about how quickly they can join the flock, with some leaving here exposed from day 1, others keeping them separate but visible for 3 weeks or more. (I did that, but because I wanted to keep my broody separate for breeding purposes)
It really is a mixed bag, with time of year, set up, climate, age and breed all changing what will work best.
Most important though, seems to be to not try to move her until after they are hatched and fluffed (day 2 or so). I wish you good hatching!

