I have just bought about 12 bantam chicks from tractor supply. My question is when they are fully grown can I put them out with the regular chicks or do they need there own space away from the other chickens and 1 rooster any advice?
You should be able to place your bantam's with your regular flock once they are old enough to get out of your brooder. At this time you will want to start the process of introducing both groups slowly. I would use some temporary fencing to keep your bantams in for a day or two...next to your other group. This should give you a clue as to how the breeds will react to one another.
Next, you will want to begin to mix both groups if everything has gone okay. Make sure that you watch them closely and make sure no one is getting hurt. Since your bantam's will be smaller than your general flock you might want to have additional feeders/waters which are smaller. This should promote them to continue to eat/drink without a problem.
Personally, I have bantams mixed with Jersey Giant's with no problem. The much larger breed does extremely fine with the bantams and acts were well behaved....