Budgies are susceptible to goiter and need a source of iodine if they are fed only on seeds. Vitamins need to be added in the water, but the bowl or water bottle must be washed daily to prevent bacterial over-growth. If the bird eats a pelleted diet, no vitamin supplements are necessary.
The rate of cancer is very high in budgies, which may be a reflection of a chronically poor diet. Budgies shell their seeds, so vitamins added to the outside will be discarded. For those using a seed diet, it is a common practice to give a budgie a large bowl of seed (relative to its size) and leave it for a few days. The bird will then leave the shells in the feed cup as he eats, and the cup full of shells may appear to be a cup full of seed. This may lead to starvation.
Contrary to popular belief, budgies do not need grit, but they will eat it. If they are in good health, grit will not harm them. If, however, they don’t feel well they may overeat, which can result in an impaction.