Personally with beginners I do not like to do Groups, I think they need too much attention. I have done 3 in a group that were walk trot cantering.
I do not think until then they have enough control. Just my thinking.
"you can only ride the drama llama so hard before it decides to spit in your face." ?Caffeinated.
We had groups of eight to twelve at school and were directed in lots of four. It was actually nice not to have the individual attention and be able to work things out for yourself without scrutiny. The instructor has to be up to snuff though.
I like to start complete beginners one on one, or two kids with them taking turns riding/other leads the pony, when possible. If you have experienced helpers on the ground, that's different.
Once they can steer at the trot, they are OK for groups.
At one point, I had six hours straight of five kids per lesson. That meant, if I talked nonstop, each rider got twelve minutes of instruction. You really had to plan the lessons and have a good strategy to keep everyone moving and comment on everyone.
I prefer three, ideally. Of course, more is great for income. But with three, they can watch each other, do some fun games, one can be recovering, one getting ready, one doing a little individual work.
Also, my insurance premiums go up at a certain number of students per lesson; I don't recall exactly, think it might be around six.
For confident beginner who are WTC I have seen successful lessons of up to 5 where the instructor did group games and had them practice new stuff individually. Intermediate lessons of 2-4 seemed to work best because the riders got a solid hour in the saddle but there was down time to process and give the horses a break.
A barn I once rode at goes with the policy of maximum of 6 students for the very beginners (walk/line-trot) and up to 8 for (walk/starting group trot). Many times the very beginning classes have an instructor and at least one assistant. I can't really comment on why they structure their lessons that way since I wasn't an instructor, but as a student I didn't really like it when I ended up in a large class. I felt like I spent a lot of time waiting around and often the instructors couldn't see everything. It wasn't anything against their expertise or judgement, it just seemed to me like they had too much to look at.
back in the day, group lessons were the norm in the Old Country.
Depended a bit on the instructor/venue, how many. I am thinking 8 were the norm. Most of it was head to tail. At the beginner level, with good schoolies, that's pretty much all you need: TITS, Time in The Saddle. The instructor would remind the whole group about sitting up, toes in, heels down, explain how the move is supposed to be set up, etc, then for the canter work the group would ride around in a walk, the first rider would canter, then rejoin the group by lining up at the end. By the time everybody had their turn the leader was back out front. One hour classes.
of course, how much attention each rider gets can also depend on whether or not the parents are in the bleachers....
You didn't go private until you were really good.
When I have ridden in group lessons I've felt that 4 was the max that worked well. I once watched a group jumping lesson with 8 horses! Those girls spent more time in the halt than they did going forward and flatwork was a nightmare.
Depending on the particular kids and the ponies/horses, I'd say four is a good max, five is stretching it, and six or more is too many in most situations. In a riding school situation with "nose to tail" docile horses, I could see a larger group working out just to get kids riding time, but that isn't the same as a lesson exactly. Personally I think lessons with 3 or so kids are great--the kids learn from each other but don't spend too much time waiting to do an exercise (if jumping is involved) and the instructor can give each kid some individual attention.