I also wanted to mention that this is her first broody session! Maybe she didn't turn them right or distribute the heat right. Thank you for everyone who helped. about to do a float test. I will keep you updated on the float test results!
So many things can go wrong, or right, in a broody situation and often you never know why they didn't hatch (and sometimes how they ever hatched).
It unfortunately is trial and error until you find the right solution for
your situation, and with each brood you learn something new.
I have had hatches that *should* have been perfect, but were dismal. I have had eggs that should never have made it, but gave them a chance, and healthy chicks came out.
There are so many dynamics to consider, and it takes time to work through the possibilities to see if there is a pattern that shows a problem, then fix that problem (hoping you don't create more problems with that fix).
If you are working with purchased eggs, especially expensive ones, it is best to isolate the hen completely, provide good nest materials, good food and water nearby, and interfere as little as possible.
If you have the advantage of a rooster, are not handling expensive breeds (to sell or breed), and a calmer flock (which happens with a good rooster), and can handle some "natural loss," you may be able to be more relaxed and "let nature take its course" on the farm.
I've been the former and now am the latter.
When I was purchasing expensive breed specific eggs while building my flock, you bet I hovered over those eggs and hens!
Early in our chicken years, we burned a full size coop down, to the ground, to ash heap, with a heat lamp, overnight with a blaze so hot that it scorched nearby trees and left nothing but the hot metal hardware and a smoldering ash pit at morning light (NO one had seen it or called the fire department!) So the idea of hot lamp brooding in the garage had waned considerably (it is the hand of providence that kept the whole property, and our neighbors wood pile, and our neighborhood, from burning to the ground with that coop fire...I could have become another Mrs. O'Leary).
So when I had a broody volunteer that spring, the idea struck me, why not try the "natural" way. She gave up (a Buff Orpington as it happens) and didn't go broody again, so I purchased a known Silkie brooding queen. I bought really cheap, mutt eggs, from a farm as her first test batch. She was in the main coop with my flock of large fowl, and I ran into problems through that first batch. Hens were laying in the nest, kicking out the fertile eggs. She was pushed off the nest leaving eggs to get cold. So I ended up subdividing the coop with a couple of boards and nails so she had a small area to herself. She hatched 3 of 3 eggs for me....but I learned with her, I would need isolation.
So we built a broody hutch, and I placed her in that when she went broody. I hatched some really nice quality, expensive breeds with her (BCM, Rhodebar, shipped Buckeye eggs, and more) as I built my flock. My problem was integration....I would open the grow out pen to let them integrate, and the chicks did pretty well, but my flock would always severely haze that poor silkie....even the very chicks she had hatched earlier now as adults would haze her!
So, I built a bigger and better grow out pen, and was planning to get another Silkie to keep Oma-San company as she would spend all her days in that....when, as Murphy's law would have it, a Coopers Hawk picked off my most valuable player on her last outing day with the last batch of grow outs!
Broken hearted, I scoured and found another proven Silkie and purchased 2 bantam Cochins for this fine broody hutch and grow out pen. And I've hatched a number of very expensive breed eggs and fostered various breeds until I have gotten the breeding flock and finally the rooster I want.
Now I've got fertile eggs and a breeding plan, and an amazingly calm flock with the most awesome rooster. When I had several full size hens volunteer in the main coop this year (I normally would put them in the broody hutch, but often had troubles with the large hens with the banty hens requiring some clever partitioning...and work), I "let nature take its course."
I'm working in small batches as I "troubleshoot" this set up. I've had some issues with hens laying in nest boxes,and I think one chick got crushed because of that. I've had one momma abandon her hatchling too early (at about a week of age) to stay with the flock, so I used the gal whose chick was crushed to foster that abandoned young chick (worked wonderfully, but then foster momma of course abandoned her second set of eggs I'd given her at day 14....which went to the broody hutch and my banties who had gone into brood again...being serial brooders).
So I'm going through a learning season of "musical nests" trying different ways to do things again. Learning how to do different methods most effectively, and that certain methods are better for certain situations.
The rooster has made broody hen integration and chick flawless...nobody gets to mess with momma and chick, no snotty gals allowed around here, yet tenderly cares for his ladies and babes. (I LOVE him!).
My banties, who are always hazed by the large fowl (and hawk bait for the multitude of hawks we have) remain safe in the broody hutch. These gals brood throughout the year, so I will use them for really important hatches that I want better control over.
So there is no right/wrong and every brood is different...even with the same hens...and some you win and some you lose...that's life with chickens. Again, you learn something new with each brood.
As to your gal, set eggs under her again if she is a stubborn broody, but if she shows signs she's had enough, let her get back into the flock. You can urge her back in by gently taking her off the nest and setting her into the yard away from her nest. Giver her really yummy treats each time. After a few days of this kind of treatment, those that are ready will break and join the flock. If they stubbornly insist on sitting...I put more eggs under them or fosters since a chick is the best way to break a hen from a brood....if you want to use that hen for brooding again.
My thoughts.
LofMc