Oh yes, it might be the lack of a nesting box. She could be looking for a place to lay. Have you ever visited the poultry area at the state/county fairs and the hens are bawking and pacing? They are looking for their comfy nesting boxes and can't find them and don't want to lay anywhere else. You know the recycle bins? I fill those with straw and it works fine. They can sit low and protected. So if you do let them out your BR might dissappear and find a nice protected area to lay. If this happens, she will want to lay there all the time so it is best to have her learn to lay where you want her to, in the tractor.
Some very interesting stuff in this thread. I hope no one minds my putting my 2 cents in.
I have a pullet who was living in a friend's yard for 2 weeks (we guessed her to be about 8 weeks old). I took her home (long story), got her a coop and let her free range all day. At night, she would roost in a tree unless I lured her into the coop. That's been working okay for us although she won't go into the coop on her own except for a quick snack during the day.
In the morning, she paces in the coop until I come let her out. She seems quite agitated. Lately, she's been better (it's been about a month and a half now) but still balks at going into the coop at night.
I attributed her behavior to her being "wild" for the first few weeks of her life. I'm hoping that when my chicks are old enough to go into the coop she'll want to be in there with the "gang". I'm REALLY hoping she doesn't teach them the joys of tree sleeping!
She's a black sex link, approximately 14 weeks old. Today she seemed quite agitated I guess because I moved the nesting box back into the coop from where it had been. From the number of feathers in it, I guess she's been spending a lot of time in it. I'm hoping its presence in the coop will make her more at home there.
We're working on increasing the size of the run and the coop.
Just remember, no good deed goes unpunished! I rescued a chicken and now she runs the house. Don't tell the dog!
I try to give my girls some time to come out and 'play' most days. They actually go nuts when I ask "Do you want to come out and play!?" One of the main reasons I do this is that I want them to have time to do their natural activities - scratching, pecking, bug hunting, dust bathing etc.
If you can't do that as often then I would try to substitute with something in the tractor that will stimulate them.
I have lots of space as well, but I make sure to giive them lots to do anyway... I will throw flakes of straw in for. Them to scratch around and peck at. I tie chains up and screw in a cabbage head for "tetherball" (which they LOVE). I give them the stalks and heads of "done" suun flowers to peck at.
Chickens get bored and need things to do all day long. Its not enough for them to just have a space to walk around in. They are designed to peck and scratch ALL DAY....so you need to provide them with things to do if they can't wander about all day to forage.
Well, here is the promised update: I installed a nestbox into their run a few weeks ago (a covered cat litter box, as many here have recommended, filled with bedding) and the birds love it! All of them now do their laying in there. And the agitated pacing behaviour has totally disappeared. The poor dears just wanted a better place to lay their eggs than under the waterer in the grass.