The sixth known foal to be born this year is Petra, a filly born to the mare Galena. I am going to say this is a Doc foal, since he had this band since May of 2014.
Galena is the 2006 daughter of Blanca and Lakota. Doc is the 2003 son of Winnemucca and Littlefoot.
Thank you Jack Sterling for sharing your photos, we all really appreciate it!