I might just be confused and ignore me if I am but if your storage is full, feeding and watering is automatic

Yes but instead of having to select horses to use it, if you have employees you don't have to check all of the boxes on the horse pages, the employees just do it.

It sounds like the issue is going through every horse to change it to boarding at home and eating/drinking from storage, is that right? So maybe like a Mass Action to "board all at home" and then "all eat and drink from storage" would make that easier? Once they're all switched over and saved to eating/drinking from storage you shouldn't need to visit each horse to care for them, just refill the storage from estate management.

That would be helpful too. Any possible way to make mass feeding and watering overnight occur without having to click a ton. I'd even pay ingots for it if needed

That would help a lot if you have horses for stud/brood too, I'm fairly certain you cannot use outside studs or broods if they haven't been fed and watered

I dunno I guess I still am confused because I always put my horses in my own boarding and to be fed and watered from home and I do it as I get them so it takes two clicks and they are set for life. I just gotta refill the storage. I suppose if you had multiple horses you wanted to switch over a mass action would be nice for that but otherwise, I dont see it as an issue. 

However, I dont use employees, no need, so I dont know how they work or what could be needed there