A. Round cages are not recommended for most bird species, for a variety of reasons.
The first reason that these cages can be bad news is because they can be detrimental to a parrot's psychological health. Birds are very intelligent creatures, but many have driven themselves crazy climbing around and around cylindrical cages, and feeling like they're never getting anywhere. Giving a bird an angular cage provides them with reference points to different locations in their territories -- thus helping them feel confident, safe, and secure.
Another reason to avoid round cages is because they are often awkward living spaces for a bird to inhabit. They very way that they are shaped causes many bird's feathers to be in constant contact with the cage bars, wearing them down and giving the bird a ragged appearance.
Round cages can also be difficult to maintain. Because most bird cages are now square or rectangular in shape, it can be hard to find certain accessories that will fit round cages -- like cuttlebone and millet holders, seed cups, and cage liners. For this reason, it may be easier on both you and your pet to opt for a square or rectangular cage. By doing so, you can provide your pet with a comfortable home, and provide yourself with a cage that is easy to keep clean and well stocked with fun accessories.