@Mildgyth
i guess they have evolved past that since they don’t have harems
(unless like humans are mostly royalty in older time periods but it was a different time and a social thing) and they can eat foods with chocolate and other foods regular horses can’t eat .
but what about this
Mares are seasonal breeders that cycle from about early May through October. A normal cycle consists of roughly seven days of estrus and a 14-day period of diestrus (when she is not in heat)
i found this on the internet but is it still the latter right? since you said it does not seem to be the case because otherwise, ponies birthdays would have been only in certain months when in reality is any time of year a pony is born?
so basically it does not matter ponies have evolved past a mating season and mate any time of the year? because ponies are the majority and have spread out a lot in the the land of Equestria