She's been sitting too long if 4 MONTHS is an accurate statement.
You did not use effective means of breaking her... as I have battled the broodiest of hens with success, time after time...
@aart please share your set up for future reference, as I don't have any pics but use the same method. TIA
IF you are going to get her anything... it should be LIVE day old chicks and NOT hatching eggs... at this point her condition will be greatly diminished and she is likely verging on death from malnutrition. If it's a typo and only 4 WEEKS... Still birds under 6 days old adopted to her after dark is the best suggested route if you have room for more birds. I would not do quail as I don't think they will stick around. Turkeys is questionable since they don't speak the same language, but doable. People have even done ducklings. Turkeys have higher nutritional need than chicken chicks and require appropriate 28-30% protein game bird or turkey starter feed. What is your hen eating? How old is she? What breed?
Purchasing from a feed store or hatchery may also allow you to get females and less likely to have to deal with cockerels in the future.
They will hatch anything... even air!
Glad it wasn't the fox! Now you know she is a nest hider.