Choose a right size cage for your bird When you choose the cage for your bird, please keep the size of your bird in mind. It is always better to buy the largest cage you possibly can for your bird. Keeping a bird in a cage that's too small can lead to undesirable behaviors such as screaming, biting, psychological disorders, and feather plucking, to name a few. A good cage should be large enough for your bird to walk around comfortably, and fully extend and flap her wings. Consult your avian veterinarian for recommended cage sizes for your particular one before you purchase this cage.