my horse holds water in her mouth. is this normal?

My horse is about 5 years old, and she holds water in her mouth. Is that normal? do i need to get her checked by the vet? She has enough water and eats great, but she holds water in her mouth. Im not sure what is wrong with her.

She is 5 years old and still a baby. This is probably a brilliant game in her eyes! It is most likely nothing to worry about but if you are concerned then by all means ask someone to check her over. I expect she is just exploring the capabilities of her mouth and water is great fun!