Did only one baby hatch? I never heard of parents feeding all the babies except for one. Mabey they are just not meant to be parents. Iam not sure about breeding but having only one nest box in an avairy full of tiels does not sound that good. You would think that the parents would have a harder time protecting their nest box, ect. If you get them I would make sure you are prepared to hand feed the babies if you decide to breed them.