The needs of a chick (a young bird) are very different from those of an adult bird. While adult birds can eat canary seed and other hard foods, chicks have a less developed beak and digestive system, so you must adapt the food to its stage of growth.
On the market today, it is possible to buy a multitude of bird feed that is suitable for chicks. The products available are mainly powders to which hot water (about 38º) is added, stirring carefully to avoid the formation of lumps. The mixture is then placed in a syringe to feed the chick directly in it's beak. In case of an emergency or you run out of speciality baby bird food, you can make a homemade porridge using a boiled egg, breadcrumbs and water.