Hello Mrs. P.
I would mix them - gradually - but as a general rule make sure they are similar sizes before you do so.
If you can put the newcomer behind a fence to start with so they can get used to her, that will help then after a week or two, pop her into the coop at night to roost with them. Be there at first light to make sure there are no serious fights.
It can be vicious until they re-establish the pecking order and you should leave them to get on with it as much as you can (unless blood is drawn and then you will need to intervene, removing the damaged hen.) If the fighting is serious and caused by one hen (this hen is most likely to be at the top of the pecking order), remove her until the others have settled and then re-introduce her in the same way.
05 Any thoughts? Many thanks
