Sick hen?

[Muaaz]

My new hen I added to the flock has been looking so down it’s always alone , lays on the ground and sometimes even sleeps mid day, why is it??

 

[Yardmom]

You say it is a new hen. How new? It could be hiding from the flock. Did you quarantine first? Was it acting normal before? It could also be signs of illness.

 

[Folly's place]

Welcome!
I'd guess illness of some sort.
Did you isolate her for a couple of weeks before introducing her to your flock?
At night with a flashlight look for lice or mites, and treat everyone if you find any on any of your birds.
Is she eating and drinking? Do you have more than one feeder and waterer, so there's no competition for these resources? Are your birds keeping her out of the coop and roosts?
So many possibilities, and any move is stressful, bringing health issues up that might have been simmering before she arrived. From where? A healthy flock, or ?
Mary