Depending on how your nests are set up you can try locking her into the nest when you see her at her preferred spot or looking to head towards there but that's more of a brute force approach.
I had one hen that was being very difficult about it and laying in all sorts of annoying locations...
When I make jam I grate sour green apples in with the other fruit (like strawberries) in lieu of a pectin packet. It'll be more loose than store bought jams but still "gels up."
How long as she been "boycotting" the nest box? Depending on how the coop is laid out you can try blocking off or messing up the area she's chosen to nest in, to make the actual nest boxes a more appealing location.
x2 on the clutter https://www.backyardchickens.com/threads/a-cluttered-run.1323792/, I think the lack of hiding options goes hand in hand with their reluctance to venture out because the only good safe spot they know of is by their coop.
If you can free range the older birds even for a bit with...
Very normal that they don't get handled, though funny thing for me - the feed store lot where I got my picked over pullet had a lot of roosts set up, so another pullet I got at the same time knew how to roost and taught all my other chicks (same age) to roost as well.
The picked over bird was...
Hard to say if there's no noticeable issues. Although the lower roost looks perfectly accessible to me, have you tried a very moderate ramp or maybe steps made of pavers to see if she could use those to access the roost? Either that or I'd persist in putting her on the low roost at night to...
My guess is you're correct, they were being picked on because of crowding or possibly being mixed with older birds. Young birds molt and refeather rapidly so they should start looking better soon.
Like this chick came looking picked over from a feed store lot:
Same bird 12 days later:
Sounds like your birds already get a variety of things to eat so a vegetable isn't as interesting. And every flock will differ in their likes anyhow.
I very rarely deliberately buy anything for the birds, but they don't mind leftovers. Melon rinds, corn cobs, spinach stems are all popular...
I would try a broody but it has never lined up with when I plan to get chicks (and almost always a hen goes broody after the fact! :p)
Deep litter on the run floor. It deliberately exposes the chicks to microbes and bacteria present in the environment to help bolster their immune system...
She probably has just enough hormones to kind of trigger the desire to seek out a nest site for laying, but not enough to trigger laying itself. Like I have one bird that spent much of springtime convincing herself that she was going to lay (she didn't, but she would sit down in the nests on...
Small mice can get through 1/2" so if that is a primary concern then that could help. But raccoons and dogs would have a easier time getting through your typical 1/4" compared to 1/2" simply because the wire is thinner.
I get how the Garden Coop style works but 2" gap on one side doesn't seem like enough. Can you drop one or two of the boards on the inside wall of the coop to allow for more airflow? Like this, removing the part in red and framing it out with HWC:
Also you're better off with 1/2" HWC for...
And secure it throughout, not just at the perimeter of the HWC section(s). You can weave wire, reinforce with zip ties, or I randomly placed hog rings throughout the length and width of the HWC.
Yup I have a cluster of trunk rounds in the run just as clutter and one's already sawdust. The chickens enjoy dustbathing in the remnants though so it still serves a purpose.
Cinder blocks are another good option, especially if steps are needed outside as they don't get slippery like wooden steps or a ramp would when wet from rain.
He's young, and younger birds go through multiple small molts as they mature so not unusual to see picked areas re-feather themselves without need for a full molt.
It probably depends on if she finds you suitable as the "rooster" but mine don't accept a human escort as a substitute.
Really no reason to be putting her in the box (if she was already laying and not using the box, that's a different matter). It's probably just stressing her out.
Some...