They need to build a pheasantry first. I fancy a quiet, cool site near the cheetahs. Then stock it with these monals, plus tragopans (satyr or Temminck's) and pairs of the Edward's and brown-eared pheasants that are off-show (according to the Annual Report). They could add some Asian passerines, such as laughing thrushes, or doves or even some of my favourite Derbyan parakeets (which are no longer on-show at Chester).
From memory I seem to remember nice Pheasant aviaries a long while back in the areas which have all been demolished. Can't imagine those type of aviaries returning.