I currently have a large chicken coop / run that houses Japanese Bantams, Fancy Pigeons, and now a flock of 13 Parakeets / Budgies. I am amazed they all get on great with no fighting. I would never have tried this intentionally... it happened by accident. I always kept each kind of bird separated. But I moved house.. and build a huge chicken coop / run thing. I moved my bantams into it straight away.. and I had no time to made a coop for the pigeons.. so I added them as a temporary measure while I started the chicken coop. The chickens and pigeons get on fine. (I am not allowing them to breed in there.. I know the chickens will eat the squabs... I always cage breed my pigeons as individual pairs anyway). My budgies had to give up their aviary at the old house.. and I put them into a large flight cage. I moved this into the chicken coop... as there are a lot of cats in the new area. But the cage would not fit on the shelf in the coop standing up.. so I had to lay it on its side.. which the budgies loved as it gave them more roof to fly back and forth. Now they are so clever!!!... after a few days they learnt they could slide the food dish doors on their cage open.. as the cage was the wrong way around.. so gravity did not keep them closed. I went to feed the birds and was shocked to see budgies happily flying about in the chicken coop.. going in and out of their cage to eat and drink. At first I panicked... thinking the chickens or pigeons would peck them.. or the budgies would peck the pigeons feet. I watched for a while.. everyone was getting along fine. The were all feeding at the chicken feeder... it was amazing. Then I was worried I would not be able to get the budgies back in their cage. But even that was so easy. I only had to put in some vegetables (which they love) and herd then gently back toward the cage.. and they all went back in through the doors very quickly. I did not have to chase any or grab them. And none got scared. They are all very tame. This week they can come and go from their cage as much as they want... but I lock the doors in the evening ... they all go back in on their own to roost. Its great.. as the cage doors are too small for the pigeons or chickens to get in.. so they can't steal the budgies food. Its such a strange combination of different sized birds.. I would never have thought it would work. Even more amazing they are enjoying free ranging!!! They can squeeze through the small gaps in the metal roof... and fly about in the mango trees. They come and go through the holes... But I thought this was far to risky... with the cats... so after a few days I sealed up the holes. I never thought they would come and go just like my pigeon.. perhaps they learnt from them? But its not going to last much longer. I am already building the budgies a new aviary.... I want them to be in a beautiful ornamental aviary in my garden.. as a display thing.. not in a chicken coop!