Thanks for sharing your story and insight. Happy to hear your girls are (still) good producers. Three is a good age for a production breed.
We were below freezing last night and the two were huddled so close together when I checked on them, Goldie was almost crushed in the corner.

I know they love each other's company. Not good for a hen to be a loner. Those girls cannot get here fast enough. I figure the newbies will actually help her or the stress of it all will make things worse --if -- and hoping she makes it that long.
Was just out with the girls for some free range time. It's windy as all get out - 15 mph sustained out of the NE. Goldie was actually eating greens and pickin and peckin today - every day is literally different. She was even waddling and trotting around. She tires easily so I watch for standing and preening, then it's back in. I have them tarped out today given the sustained winds and she is standing in the corner away from the wind where it's calm. I don't want her to get chilled. The sun doesn't really have much warming factor given the wind.
Chickens are quite the adventure and we never know what to expect given how things can turn on a dime.
I'm glad Goldie is doing well today. That's comforting. Hopefully this cold snap will finish soon, so we can go back to regular cold weather instead of this below zero stuff - it's just not normal in Alabama either, and my girls don't like it. Sounds like you're having a wonderful day with your girls, wish I could do that!
Since this is your first replacement flock, I don't know if you've run across this info before, so I thought I'd mention it - old girls and new pullets don't become "one flock" until everyone starts laying eggs. The pullets will be their own sub flock, and the old, currently laying hens will be their own (much more important!) sub flock, who will delight in lording it over the youngsters. The old and young flocks will probably roost in different locations if given the opportunity, and the older hens will hang out in the most desirable areas of the coop/run, and chase the youngsters away from any interesting food until they've had their fill, etc. If the coop is too small, you may have trouble getting the youngsters to go inside at night, because they're trying to maintain distance from the older hens.
Always make sure there are areas the youngsters can run to to "hide" or "escape" from the older hens - mainly areas that are shorter, with narrower openings, lots of run clutter to break up line of sight. Make sure you have multiple feed and water stations so the older hens can't guard them all from the younger ones. You want the young ones to be able to sneak up and drink or eat without the older ones seeing them and chasing them away. I had some pullets that would literally hide within pallets (not under or behind, but inside them!) to escape from older hens. I had to carefully fish one out a couple times once she started getting a bit too big to fit.
Once everyone starts laying, the older hens will allow the youngsters to roost with them, and they may become one flock, although you may see the older hens still prefer the company of their older flockmates, and insist on being "head hens". Over time, the pecking order may shift as youngsters get bigger than older hens, and/or become more confident, but that can take months to a year after start of lay. A laying hen is not fully mature until after she's gone through her first molt around 18 months old, you may even see some plumage change in some breeds after that first adult molt.
When hens go broody there is a large hormonal shift also, whether they raise chicks or not, and that can help certain hens become more confident. I had one hen that was middle of the flock, who I let sit and raise chicks during her second year, and she went from middle of the flock to practically head hen while she was raising those chicks. Once they were 2-3 weeks old, I opened up the gate so she and her chicks could mix again with the rest of the flock (they'd been in eyesight but not physically connected), and my broody momma attacked every single hen who came near or tried to mess with her chicks, including the head hen. I was so proud of her - she was an awesomely protective momma to those chick, absolutely confident and fearless. As a result, everyone left her alone. Once chicks were raised, her hormones went back to normal and she wasn't so confident, so she went back to mid-level again, but not as low as before. It was a fun process to watch.