Robbie wrote: Now this may seem like a stupid question, but how can I find her?
It's not a stupid question, but no easy answers, wait until she comes out and follow her is what I do. Some are wily and will take you on a wild goose chase and disappear in a blink. Not all will come out every day, especially in the very beginning and towards the end. I have a few that once they start sitting, they don't budge for three or four days, but then nature wins and they have to get off to

...and will usually run for a quick bite of food while they're up anyway. Literally, run, munchmunchmunch and run back. If they don't have access to food, they will not wait for it, they're back on that nest and in Zen broody mode faster than you can blink.
Robbie wrote:I figure she'll be on the ground somewhere, pretty close to where she used to lay her eggs-
Not likely! If she felt her original favourite spot was in danger of being raided or disturbed, she could be anywhere. Ground is most common place to nest, but they're not always logical creatures left to their own devices. I once had one decide that on top of a barn beam in a loft, was a GREAT place to lay. I only found the spot because I found smashed eggs on the threshing floor, 15 feet below :/ At any rate, if she has a new spot, it's probably nowhere near her old one if it was rearranged or disturbed in any way.
Robbie wrote: does anyone have any other ideas where I should look? Surely she won't put a nest away from where the chickens usually roam?
Behind anything that stands out/up from the wall/floor in the slightest, like open doors, under stacked lumber, behind leaning building materials, in gaps in straw bales, under wall edges, behind loose housewrap or siding, in crawl spaces, in coop eaves. under porches, under low trailing trees and bushes, in hedges, under brush piles, in an open composter or unused garbage bin. They will get into places you wouldn't think them capable of, just to stop you from pilfering their eggs :D
Robbie wrote: I'm sure the weather will turn soon, no way she'll make it outside for 3 more weeks....
She absolutely could. Cold weather will wear her reserves down faster, but chances are good she's in a reasonably dry spot, which is most important in cold. Her eggs may not be so lucky--when she gets off to eat they will cool FAST, and won't survive repeated severe cooldowns...but if she IS broody somewhere, she will not sit a nest for three weeks straight, she WILL come off it occasionally, and hopefully broodiness is the case here and you can find her/catch her. A dog works well too as Ross said, and may show particular interest if a predator has recently been hanging about as well. A snatch and grab by a fox doesn't always leave evidence behind, except for a smell most interesting to a dog with a high prey drive. If you are concerned she is holed up and the dog may harm her before you can correct, use a halter, gives you instant control of the dogs face/head and even a big dog can't pull you. My oldest son has a King Shepherd, he's enormous and pulls, making walking him anywhere there might be small animals a bit dicey without a halter, but with one, it's a breeze. No dead chihuahuas or chickens lol
I really hope you find your girl!
