Hmm I would try separating them with something like chicken wire or poultry netting-that way they can still see eachother, but not attack one another. Then, after a time, gradually reintroduce them and let them work out the pecking order while being supervised. After that, if theres a hen or two that's just too aggressive constantly I would rehome them Hope this helps! Good luck!
I have game hens with spurs and they will fight just like a gamecock. So separation is necessary sometimes. I have one hen that has to be seperated from all other hens and roosters. Shell fight anything. But still gives me 5 eggs a week
If they are just pecking a bit at each other then tending to go their separate ways, they should work it out eventually. If you have one aggressive hen picking on everyone or a few of them constantly and causing anxiety and or injury, separate her for at least a week and try again. Sometimes, like sorrowsmiles says, it's best to rehome responsibly or eat the aggressive hen. Chickens have personalities, as I'm sure you've witnessed, and who needs a bad hen causing injuries when there are so many great birds out there?