i have 4 Banrevelder bantams (1 is a rooster) and 2 light sussex bantam hens. I'm thinking of getting some more hens but would like to get some standard sized ones for bigger eggs. Can I keep all the birds together in one run (it's about 8 ft x 25 ft). I'm assuming that there will be a bit of bullying until they settle into their pecking order but I don't want to cause any undo stress or injury.
They should be fine depending on how many you get. How big is the coop? One should always quarantine new birds.
If you get the new hens at about the size of bantams (8-12 weeks old) they will more readily submit to the bantams as juveniles. They'll retain that until they're mature, and at that time, they'll be good and used to them and you shouldn't have any issues. Getting older hens will require a more extensive introduction period, depending on the attitudes of the Bantams. With the run size, you should be able to add 3-5 depending on the coop space for roosting. Bedtime is the hardest part, when the new birds have to find their spot on the roost. It is a good idea to quarantine if you have the space to do so. It wouldn't be a bad idea to corner off a section of the run to put the new birds in, so that they can meet and greet without direct contact. Letting them see and hear each other for awhile first usually makes the transition easier. I do that for about 2 weeks.
I have silkie bantams and have tried to mix them with standard chicken,and it was a disaster.Although every situation is different.Just keep a close eye on them.ChickenCanoe is correct they do need to be quarantined for a few weeks.It also would be better if you raised chicks in with the bigger,just in a safe cage inside the coop.