I am going to be keeping them separated from the older ones for about 3 -4 months before introducing them - I have to keep them indoors ( got an old school building I can use ) because we have some foxes around that can cause a problem .
My current lot ( 5 hens - 2 roosters and a duck ) are a bit beaten up at the moment - the two roos got in a bit of a scrap last year, one got partially blinded and the other ended up with a broken leg ( which we set ) so one can't see where he is going very well, the other limps quite a bit - added to this a fox got in the other night ( I was a bit late putting them to bed ) and stressed them all out, but thankfully no fatalities as I arrived almost the same time as the fox - hope you don't have that problem where you are.
I will post some pics of the new arrivals when I have some.