As long as the parent species are closely enough related, all chicks should be born rather healthy. Much like breeding a horse and a donkey together, only 99% of hybrid parrots are fertile. The chicks may actually benefit from what is known as "hybrid vigor", in that they have more genetic material than both parents, and may benefit from it.
That said, personally, I prefer to see hybrids that are clearly hybrids (like many, but not all, hybrid macaws that are clearly hybrids) instead of hybrids that could be mistaken for a pure species (i.e. sunday conures or some macaw hybrids bred back to one species and the resulting offspring look near enough to that species that, if not for some very minor changes, could be mistaken for a pure - catalinas and miligolds bred back to blue and golds can look near identical to blue and golds... or another hybrid, if not for the shape of the head, a cherry head x blue crown conure hybrid could be mistaken for a white eyed conure...)