Region specific, definitely. For full board, grain is included; usually so is blanketing, fly masks/fly spray in the summer etc.
Many people choose full board because going to the barn every day is out of the question, let alone twice. I make it out 4 to 5 times per week, and can do that mostly because I work from home 3 days per week, or when I was part time it was easier. I’m more involved in my mare’s care than some of my fellow boarders. People who can afford high end barns tend to have high-responsibilty jobs, travel extensively for work and so forth.
At the level of barn where I board, tacking up, grooming, cleaning tack etc would not be expected of the barn staff. Horses and owners are not “in a program” like they are in kirbydog’s facility. (I honestly would hate that!) Vet-ordered treatments like soaking a hoof, providing medication that can’t just be thrown in the grain, limited hand walking, holding for vet and farrier etc are included. At other barns these things are extra charges.
Some BOs prefer full board because neglectful treatment from owners is an issue. How many times do we read about people stealing other peoples’ grain, hay, etc? Or horses in heavy blankets on 60 degree days? Skinny (or fat) horses because the owner is weird about grain? The horse owner pays for grain one way or another anyway, whether buying themselves or as part of board.
Every barn I’ve been at charged extra for more than 2 grain meals per day, extra hay, etc.
It’s just another way of doing things. BOs who cut services might experience more hassle.