Dominance in The Coop

[Cochin4000]

I’ve never had chicks before until this year. I got 4 to begin with, and when these 4 were about 5 weeks, I got 7 more chicks. I introduced them and they hit it off. Then they started living together and they do ok together. The 7 little ones are scared of the 4 big ones because of pecking order and size. Except there is one problem. Every night the four old chicks go into the coop and three of them sleep while the head hen/chick sits at the door. Later the little chicks start to go Inside only to have the head hen fight them out of the door way. I took the head hen out but then the second on the pecking order, out of the 4 big chicks, sat at the door and pecked the little ones off the ladder also. My coop is plenty big enough for all of them. This is simply a territory thing and I don’t know how to fix this problem. The older four chicks are now 7 to 81/2 weeks and the babies are at about 4 weeks. When they’re all in the coop finally, the little ones sleep under the heat lamp and the older ones sleep across the coop in a nesting box. The pecking order will change soon because I have a rooster in the younger batch. Should I just wait it out?

 

[cavemanrich]

I would have the 4 older chicks sleeping on a roost, not a nesting box. If you did have a roost available, then possibly you would not have the one or other chicken at the entrance. (acting like a sentry)
Seems nobody wants to put their general location into their profiles anymore, so I have no idea what type of climate you are in. If it is moderately warm, then discontinue heat-lamp for the 4 week old chicks. If you are in COLD ZONE then still keep heat-lamp on.
You will need two different height roosts inside your coop to accommodate the different pecking order chickens you have. The Top Dogs will crowd onto the higher roost. The Lesser ones will have to settle for the lower one.
It is just fine to have only one roost,,,,, but it needs to be long enough to accommodate all hens comfortably. I have no idea how your coop is interior.
WISHING YOU BEST,,,,,,,,,,,,,,,,,,,,,,,,,and