They don't really have a very different design from other pegasi people have designed, but I like them the way they are!!

The main inspirations behind their design is how varied bird wing shapes are and also old MLP concept art. I thought the variation in wing shape might make it easier to have a unique and differing character designs! They also got some extra feathers on their chest and ears to keep them warm in their high altitude environment.

Their biology isn't really that different from a regular horse's biology, so not really much to comment on. However, I will take this chance to say that they do not lay eggs! When they reach 8 years old, they start learning how to fly and usually are considered to have mastered it by the time they're 16 years old. Fun fact, Rearing Redwood equines age much slower than real life horses! They're not considered adults until they reach 20, they look similar to a 4 year old horse in our world. One day I need to do an aging chart!