Too big for the brooder, or just sibling rivalry?

[Half Moon Ranch]

We got started with our first batch of 5 chicks, they are Silkies and are currently about 5-1/2 weeks old.
So far everything has been fine except having to enlarge the size of the brooder three times to accommodate the growth and their teenage antics.
The chicks came from a reputable breeder, were straight run and of course we don't know for sure, but based on size we think we have 3 roosters and 2 hens.
The problem is that 2 of the big ones we suspect as roosters are basically terrorizing the others and especially the other big (possibly) rooster.
They will take a run at the others, causing everyone to scatter and sometimes take a kick toward their heads.
I didn't realize Silkies could be ornery, but these two sure are.
I'm just about done with their coop and run, but the temps have been pretty cold and I'm afraid to toss them out before they're ready to deal with the cold.

The brooder is 30" wide x 50" long x 20" tall and here's a pic.

Any suggestions?

 

[foreverlearning]

They are figuring out their pecking order, it is normal. As long as they are not injuring each other I wouldn't worry about it.

 

[Half Moon Ranch]

Ok, I guess that makes sense, but being our first time around we didn't recognize it.
I had just read that silkies are apt to get head injuries and of course we don't want that.
Thanks for the advice!