ahhh this answers my question as to how big your cage is.
Sorry to say I really think it is too small for 4 birds, even more too small for breeding 2 pairs.
You have some very beautiful keets there Inarbehsevan :)I was looking at your other pics.
I do think they need more room and they also need more variety of perches. They should have a grooming type perch or 2 like thishttp://www.petco.com/
and maybe a comfy perch or 2 like this http://www.petco.com/
Natural wood/branch perches are great too if you are SURE the branches are from a safe non toxic tree, bark removed and cleaned properly.
I can't see if you have a mineral block in there for them, but can't stress enough how important that is. A plain, unflavored uncolored mineral block.
At least 2 if not more feeding stations and a couple water dishes/silos.
One more thing? If planning on eventually letting them out for some fly time(which you should work slowly with them and get them hand/finger tamed first) you will have to go through all of your plants to make sure none are toxic to your birds
Be sure your cage is very secure hanging that way as I have seen more than a few accidents from falling cages.
Perhaps add another cage and separate them, putting the cages on cage stands?