Jurassic Tale (1969) on Netflix

While spending summer break at their father's house, two kids discover a giant egg hidden in a nearby cave system. They take the egg home and a few days later, a baby T-Rex hatches from the egg. They try their best to secretly raise the dinosaur but things get complicated when an evil scientist learns of their secret and steals the baby dinosaur. The family must work together to get their baby T-Rex back and figure out a way to protect and raise their new Jurassic friend.