Without knowing more about where the birds came from, I'm thinking they might be California Grays. Hoover's Hatchery has them and I've seen them at Tractor Supply before.
https://www.feathersite.com/Poultry/CGA/CalGray/BRKCalGray.html
https://hoovershatchery.com/California-Grey
In that first picture you can see where the feathers have been plucked where it's bruised. Those wounds will be fine and heal on their own. The issue will be paying close enough attention to them so that it doesn't turn into full-blown cannibalism.
One of my first hens turned into a plucker...
https://www.feathersite.com/Poultry/CGA/Arau/BRKAmer.html
https://meyerhatchery.com/products/splash-ameraucana-bantam-day-old-chicks
There are some buffs in the first link and splash in second, only a few pictures though.
It sounds to me like she just isn't getting enough to eat for whatever reason (small poops/goes crazy for food and scratch.) Are you sure she isn't being bullied and is getting enough to eat?
I had a hen that was losing weight so I paid more attention to them and even though she was up there...
https://starmilling.com/star-milling-incredible-lay-feed/
This appears to be OP's layer feed. Split-green, Austrian, and Canadian peas are listed. Probably Canadian, like @GreenJay mentioned above.
It appears to me the "adult" hackle feathers are just starting to grow in and they look pointier to me. Also, on the shoulder, back, and neck where the male feathers are coming in they are a much brighter white color. It also seems to have more of an upright stance.
This bird has a pea comb and...
I used to have a Leghorn that was the first to lay every single day. Several times I went to the coop before it got light and she already had an egg under her in the nest box. Like others said, that's just the way they are sometimes. 🤷♂️
They all appear to be Easter Egger or Olive Egger mixes with the combination of beards and crests. The bird with the crest in the first picture probably has a Cream Legbar parent. Now for the bad news. They're all cockerels. The uneven/splotchy coloring on them, especially on the shoulders is...
Midnight Majesty Marans-This bird looks like what one should look like to me, along with laying darker brown eggs.
https://hoovershatchery.com/midnight-majesty-marans
I haven't, but Ken Block has. 😲
Over the years I thought it was neat to look at the webcams and see the weather and views and imagine driving up there. I do have a question for you, though. Did you get any donuts? lol If so, were they as good as folks say? Here's a pretty cool article about...
What do the "wild" chickens in your yard look like? Without knowing that, I'd say they'd be considered a backyard mix. The light brown bird looks kinda leggy and they both have that longer tail so I might guess they could be some type of gamefowl mix. 🤷♂️ Also it looks like you have a few boys...
It could possibly be a Calico Princess. The red on them is darker or lighter on some but they all have barring and usually a little black on the neck and tail.