Any time a chicken of any age has an encounter with a predator, and dogs are very much predators to chickens no matter how gentle you believe they are, the chicken must be treated for shock even if it appears there are no injuries.
Give this chick a cup of warm water with one teaspoon sugar, brown if you have it as it has vitamins, and let the chick drink this or syringe it into the chick for the next 24 to 48 hours.
Chicks this young can sustain internal injuries easily from being caught in the mouth of a dog, even if the dog appears to be gentle. This can happen just as often to a chick when given to a small toddler to handle. Any sort of excess pressure on the chick can crush the lungs, and other internal organs. Pressure on the upper cervical region can result in spinal injuries.
If the sugar water doesn't revive the chick in a few hours, it could indicate permanent internal injuries, especially if the chick continues to decline.
To syringe fluids into a small chick, you can open the beak and squirt a few drops at a time into the right side of the beak. That's the side the esophagus is on and it's less apt to get into the airway.