You should have definitely quarantined them. You need to make sure that they are healthy and not going to infect your flock. During that time you can worm the new birds, and check for mites. It's is to late now to fix things if they are already in the coop with your girls. Now all you can do is watch every bird for any sign of illness. As for the morning I have always gotten away with slipping in new birds into the flock at night. It just depends on how territorial your original flock is. If you can carefully watch them in the morning, and be prepared to remove any bird that gets hurt.
I have always introduced my girls to newcomers at night with no problem. They just wake up, and there they are. I feel that's the best way to do it. BUT, they had been seeing each other through the fence for a couple of months also.
However, I think you should have quarantined them first to be sure they weren't carrying anything to pass on to your other girls.
I snuck my new girls in a night and it was fine, they are still working things out but there has been no blood drawn and everyone seems to be settling in. I would check for mites etc since you didn't quarantine, maybe give everyone a dose of de-wormer too.