Well that's a very thoughtful question. Water is also important to baby birds and they are dependant on their parents to supply liquids.
Some babies are brought nice juicy bugs or berries. Many seed-eating species of birds provide some regurgitated seed and water.
Crows and ravens are known for washing their food before eating. Dipping road kill or the variety of other foods they eat in water allows the babies a way to get sufficient water to meet their daily needs.