Parents selectively feeding foods to their young that result calcium, phosphorous and other micronutrient imbalances. This can occur even if the parents are offered a balanced diet and with both experienced and inexperienced parents. Some birds are just not good parents and consume the high quality foods for themselves and manage to selectively regurgitate poorly food to their babies. This also appears to occur in the wild either because of poor parenting or the chick is not aggressive or healthy enough to get a complete diet.