My chicks are AGGRESSIVE!

I bought 7 barred rock chicks and 5 Rhode Islands to eventually add to my established flock of 7 hens and a Rhode Island Red roo. I kept the babies isolated in the garage in a double ex-large dog crate until they became 70 % feathered. I then built a new coop to accommodate everyone. Since they began feathering, three of the babies attack my hand when I reach in for their feed and waterers. I flip them away and they return with a vengeance!. Two days ago I put their cage and my established flock into the new coop at night. the next morning I was in there before dawn to see how their reactions were. Those three that attack my hand were relentlessly trying to peck anyone thru their cage....when they try to attack my adult roo, "Ace" accepts the challenge and we have a pecking war thru the cage. I assume they are baby roos by their behavior and the slight development of combs. Will they try to kill each other if I open the cage door? They are out growing their cage and I need to let them out. I have no caged yard as everyone is free range. Any suggestions?

They are probably roosters as you said, they are scared and being defensive is my thoughts. They also get aggressive if they can't burn off energy and don't have enough room to run and flap their wings. I would start trying to integrate them, they need exercise. You won't know how everyone will react until you try.

Make sure you let them out when you can be there to keep an eye on them so They don't get beat up. They will probably fight if they are roosters no matter what you do.

How old are the chicks?
Are the aggressive ones RIR's?

They will either learn their place or be injured/killed.

Can you rig a small door(s) in the crates so the chicks can have a refuge?

The Barred rocks are 6 weeks? and they are the aggressive ones. The RIRs are 5 weeks and look like they are hens and very mild mannered compared to the Barreds. I opened the chicks crate and my roo quickly dove in to "clean house" I got him out immediately because he looked like he was going to commit chickicide. I'll keep trying.....wish me luck. :-/

You may have to wait a few more weeks before you can put em together. Older roosters won't tolerate young upstarts. He very well may kill the young ones.

don't rush it, integration can take some time. Expect at least a few weeks, to even possibly a few months depending on the ages, coop size and personality of everyone. Eventually everyone will at least tolerate everyone. The only exception can be if there's not enough room to add more.

I expanded my coop from an 8x8 dog pen to a 12x14 shed with a sloped ceiling that is 8-14'. I have 24 nests at 3' and a set of roosts on the other end with lots of spare room. I am going to add on an outside run until the babies can free range with the rest of the crew. Thanks for the advice everyone.