Please don't panic if you have a broody with no eggs, she will be fine. At the end of 21-25 days of it, she will come out of it, there will be no chicks under her and she will return to normal. It breaks my heart when I read about people wanting to break a broody hen- this is a natural, hormonal response for the reproduction of the species. Imagine if you wanted to have a child and your husband or partner threw you in cold water until you didn't want to any longer. Tragic.
Broody hens don't lay eggs, therefore, they don't make money and that won't work so the big hatcheries are literally breeding broodiness out of the hens, especially the big utility breeds- also, if you have a broody hen, you won't buy hatchery chicks- think of it! Honor the Broody!!!!!( hey, that may just be my new mantra

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So anyway, let her set, she will come out of it just fine- a little skinny but fine. If you have access to day old chicks, at day 21-23, before she breaks her broody mood, you can sneak out at night and put them under her and she should mother them just fine. So until then, move the nesting box to a secluded spot where the others won't peck at her, do you have another milk crate to put in it's place for the other hens? Make sure to put a bowl with food and a water that she can access, she won't eat much, but the water is essential. Keep her protected and all will be fine. If you have roosters, why not put a fertilized egg or two under her? And be proud of your little broody hen- she is doing a tough job.