Let them become older first, where they can be independent without a heat lamp and can be outside. Once they've reached this stage you can begin introducing.
Here is my method.
1. First, basically split your coop in half with chicken wire etc. This way they can decide the pecking order without conflicts. Do not let them mix with the flock yet wait about a week or so before you remove the wire.
2. Once they've established the order of things and have gotten use to each other behind the wire, you're ready to put them in with the flock. DO NOT do this during the day. Slip them into the coop or on the perch at night. That way in the morning the other birds will be like, "Oooh heey, oh wait foood!" They'll be to distracted by breakfast to think about fighting. Then they'll gradually just become part of the flock.
I've done this multiple times and it has worked for me although sometimes it is unsuccessful. Just keep trying.
QP