Cockatiels generally begin to self-feed between 6 to 8 weeks old. However, the timing of self-feeding can vary depending on individual bird development and other factors such as the availability of food and the feeding practices of the caretaker.
It's important to provide a well-balanced diet of pellets, fresh fruits and vegetables, and occasional treats to encourage healthy eating habits in young cockatiels. It's also important to monitor their eating habits and weight regularly to ensure they are getting enough nutrition and staying healthy.