Pet Chickens problem. My daughter got into hobby chickens.

I have no chicken experience but I like chicken tales.

You don't need a rooster to get eggs. They will fight continuously, and they can really wear out the hens in a very small flock. Chickens have a natural pecking order and you have to let them work out who is the boss. Make sure their pen is large enough and has obstacles to hide behind or jump up on so the lower ranks birds can escape. Logs, tree branches, even cardboard boxes will help.

You can do things to distract them like throw out scratch feed to keep them occupied. If it's safe, let them out out to range for a few hours. Offer a pile of leaves or lawn clippings to keep them busy. Give them a pile of sand to 'bathe' in, or get a shallow plastic container and put in a couple of inches of water so them can occupy themselves with a bath.

that is the problem... hens very seldom will fight like that

Pour scalding hot water over its body, pluck its feathers, cut out its innards, cut it up, and have it in the skillet of hot lard cooking in less than 15 minutes. Of those innards, she cooked the heart, liver, and gizzard too. If is was during the summer, she cooked it on a wood-fired stove on the back porch. She also did her canning there too.

Ever hear the phrase "Pecking Order"?
Chickens, like a lot of other lifeforms, create a hierarchy
or social order. pecking at (or picking on) others sorts things out.

The rose colored glasses neutralize the color red, which chickens think is blood and they attack it.

https://en.wikipedia.org/wiki/Chicken_eyeglasses

tell us what breeds you have?
Certain breeeds are known for their aggressiveness and won't work in a mixed flock.
Procon gave you the answer to your issue. They have to work it out on their own.
Once the pecking order is established, the beating will lessen but still continue.
Giving them a place to hide helps a lot. It can be as simple as a couple of pieces of plywood in a A-frame shap, just big enough for one hen to get in.
We have one rule in our flock:
"Be nice or be tasty."
Any agressive animal is shown the door. We have grandkids and will not allow any bird to challenge our little ones.

pen. This was from Thursday to Saturday.

This morning, she was returned to general population without incident. I guess she learned her lesson.

After the two days separation from the rest of the flock, things have settled down and Major Tso is not attacking the two new hens.