Installing Indoor Cat Tree

[NewChickenMum]

Hi guys, new chicken Mum here & I'm struggling to break my broody hen. 
It started 2 weeks ago with her sitting on hers & her ‘sisters’ eggs when they’d laid very early. Puffed up, growling, trying to peck me when I moved her. Once I evicted her from the nest box she was fine, ate, drank, didn’t return but every morning I was having the same problem. Had 1 day of being ok, but now she’s worse. Will return as soon as I evict her even if I do it all day. I've tried Removing all nesting/bedding materials, I’ve tried shutting her out of the coop & I’m now on day 4 of chicken jail. She’s been in a dog crate for 3 days but going back in the coop at night as it’s not fox or weather proof, but last night I put the crate in the garage. Still no change. 
How can I tell if she’s broken from being broody & not just trying to lay an egg?  She’s returned straight back to the nest box so I’ve assumed broody & put her back in the crate. 
Any advice would be much appreciated!

[Cat tails]

As soon she stops the broody clucking and showing more interest in food/scratching etc you can put her back and see if she returns to the nest. If you return a hen to the coop at night, breaking her broodiness will just take longer than 3 days in the sin bin. My Merel is broody too and just gets locked out of the coop during the day. And locked out of the run, when the others are laying. Once she starts tearing up my garden instead of trying to find her way back into the run, I know she’s ready to go back in. I do stick her in the coop at night too, because of a small garden/close neighbours issue.