What are Birdcatcher Spots on Horses?

In this excerpt from the October 2018 episode of Ask the Vet, Dr. Gray and SmartPaker Dan answer a viewer question about a sorrel horse who has little white spots all over him. Dr. Gray explains what they are, what they are called, if they should worry you (they shouldn’t), and why not a whole lot is known about them. Dan even comes up with a great way to think about them!