Chicken is staying in nesting box all week and won`t leave help?

[liamando]

She is coming up to 1 years old and this is the hottest weathers she has experienced only (23c) she is also shaking and brustling her feathers alot as if she is about to fight.

 

[gryeyes]

She wants to be a mommy! She has gone "broody," wants to hatch chicks from the eggs.

That's classic broody behavior. If you have a rooster (so the eggs are fertile) you could let her try....
One of the most heartwarming aspects of keeping chickens is having a mama hen with chicks.

 

[ladyrsanti]

And if you don't, you can suspend her above the ground in a wire cage with food and water to break her of the broodiness. Just make sure the cage has a wire bottom for good air flow. It can take a few days but I've had good luck with this technique.