OK, the one chick is fine and healthy as posted last week it's now a week old.
Yesterday the broody showed the first signs of wanting out off the eggs so I let her out for a stretch but it turned out the chick had somehow got out a tiny gap and was under the coop. After much effort both were caught and for safety, plus given nearly 5 weeks the hen had sat, I decided enough was enough and moved her and the chick to the bigger pen since it was 6 days from the one hatched chick.
Went to clear out the rest of the eggs and found one had been trying to hatch, must have been the last egg laid by the other hen, but tho I tried and tried to get it back under the hen, with other eggs, without, she kept chucking it and the wee thing died before breaking out the egg. Not having an incubator I wasn't sure I could do anything but keep trying to pop it back under, but I guess moving had traumatised it, her, both perhaps.
Today she and the chick are fine in the new place and I checked the rest of the eggs, all gone cold and abandoned. 3 more were dead at various stages of development, ie 5 of 6 from the other hen from the egg colourings, and all her own had obviously been duds. But given she was unexpectedly careful and loyal sitting all that time, any idea why the rest died before maturity? If first and last got to hatching intact why not the in between 3? One was pretty small, but two were almost egg filling size, maybe only 2-3 days short of mature. She was fed, watered, given grit and she sat all but maybe 10-15 minutes of an evening when she would come out squawking and in a hurry for a dustbath, the evening corn, a drink, and go back. She also had food, water and grit in with her after the chick hatched, but wasn't off the nest at all the last week - I had to poop scoop when she was eating.
I clearly made a mistake moving them but honestly thought nothing else would come of the eggs and when the chick got mobile enough to escape I thought they were better off shifted. I feel terrible that the last one might have lived if I'd not moved them but just put the chick back and blocked its exit point more securely, but the others didn't make it that far and before any others start sitting I'd like to have a better idea. For sure if one starts, I'll be shifting it immediately to a more secure area so all the eggs are her own and the last one dated.. What else could I have done if anything? I can't afford to buy an incubator right now and that would have presumably been the best thing for the half hatched one when she wouldn't take it back, I don't have an aga with a warming oven either..