I have no idea why the eggs wouldn't be fertile. Kazi is definitely a male, right? Maybe one or both isn't fertile? If it happens in humans and mammals it's bound to happen in birds...
My only suggestion would be to make sure that they are offered plenty of calcium, especially Kiwi. Offer a mineral block and cuttlebone; you can even grate the cuttlebone over their food dish. There are some calcium supplements that are made especially for breeding birds -- I know that Pickle's breeder uses one with her breeder parrots.
So sorry for little Kiwi and bless Kazi's heart for being such a dedicated hubby!
My only suggestion would be to make sure that they are offered plenty of calcium, especially Kiwi. Offer a mineral block and cuttlebone; you can even grate the cuttlebone over their food dish. There are some calcium supplements that are made especially for breeding birds -- I know that Pickle's breeder uses one with her breeder parrots.
So sorry for little Kiwi and bless Kazi's heart for being such a dedicated hubby!