I've had a number of horses, some very fine ones, with no papers, and therefore no precise birthday. Dawn, Pie and Red all have "official" birthdays, since they're registered - Dawn is a TB (June 10 - a very late birthday for a TB), Pie is a QH (April 29) and Red is a QH too (May 23).
So Missy deserves a birthday - most horses are born in April or May, so today's the day! We don't know her true age, but we'll just say that she turned 13 today. Happy birthday to a lovely mare!
One clean photo, and one dirty . . .