Just as snakes change their skin from time to time, or dogs and cats lose their hair, birds naturally shed their feathers. In theory the natural process of replacing feathers is simple, as they only replace old feathers by the growth of new ones. However, it sometimes becomes complicated if we are talking about sick or older birds.
If this is the case and your bird is sick or aging, the options available to you for treatment vary widely depending on the breed of bird. Generally we recommend that you always offer your pet quality nutrition (cucumber, spelt, millet, wheat and oats, as they are rich in silicic acid, contributing to growth) and food supplements such as fresh fruit and vegetables.