Separate them again if it gets really bad. I mean when there is blood. That's never a good thing. It can make them peck more.
Otherwise it should be much better in a few days. But pecking is normal.
If you don't want pecking in the future. Keep only chickens who hatched together. The same breed is best. Always have plenty of room at the feeding trough, and lots of room in general. And never keep more than one rooster.
There will always be a pecking order. But sometimes a look will do the trick and they wont peck, But sometimes a molt or some hen coming back from being broody can start a new fight for the hierarchy.
If your red hens are hybrids like isa brown. They are known for being friendly towards humans, but rather mean towards newcomers. Especially from another breed.