Watch them carefully - - - 5 weeks old chicks are small compared to the full grown ones.
If you do all I suggest - - - extra feeders, extra waters, plenty of hiding spaces, I even have a separate sleeping area for the smaller birds - - - you may be ok !
Sometimes if it does not go well - - - I put a separator up in the pen where they can see each put not get to each other. I do this for a month or two. Then when I take the divider down - - the chickens don't think it is a totally new stranger. There is still a little pecking discussion ( about a week or so), but then it settles down.