Hens plucking each other's feathers and bundling together when they go to sleep. NEED SOME ADVICE!

Just a few days ago, I bought 8 chickens which were all 8-10 weeks old. They were flown in from Vancouver into Victoria, a short flight, where I picked them up. I bought:
2 gold laced cochins
1 light brahma
1 dark brahma
2 australorps
1 gold laced wyandotte
1 Buff orpington

Today, I purchased locally;
2 barred rock
1 Lavender orpington
1 Splash Marans

Before I intoduced the 4 new chickens, the original eight were quite aggressive towards each other even though they had been together more than 24 hours and should have figured out the pecking order. I also noticed that at night, they would all try and cramp into one crevisce to try and sleep; a 6" space between the nesting box and the wall to try and sleep. They were stepping on each other and squaking very loudly to try and fight for a position in the corner. Why is this??? I have installed two 8 ft. roosting poles each at 3.5 ft. and 4.5 ft. high I know they are not too high because I have seen them get up there, yet they are not sleeping on the poles, but on top of each other on the ground. Also, after I intoduced the new 4 to the old 8 it seems that they are still as aggressise as before if not more. It's gotten to the point to where they are starting to eat each other's feathers as well as their own. What can I do to stop this. I know that they may be just re-establishing the pecking order, but this is crazy! How do I stop this????
Thanks