Rewards should be many and various.

Rewards should be many and various.
Just using a reward based system isn't enough. Modern life over emphasises  money as a measure of success. You hear endlessly how rich, how over paid the the elite is.  Art is priced, endlessly. Even Banksy's success is emphasised by what his works sell for.
By describing my rewards based system as carrot carrot, I risk the same over emphasis on one minor facet. To qoute Temple Grandin, and yes there is a risk of over emphasising Temple Grandin, but since a much greater risk for animal handlers is to ignore one of the greats, I will continue to quote her till you go out and get her books and re read them endlessly, the SEEKING circuits in the brain are the crunch.
The SEEKING circuits get us out there looking for food, money, sex, water, company or whatever floats your boat. But it is the SEEKING that triggers the pleasure. SEEKING is the search for something new. The extra lush bit of grass, the mate that isn't the one you are with, the million for those who only have hundreds of thousands, it is the search for novelty.
I take Obama out.
Yesterday he taught two new charioteers, and we introduced him to bows and arrows. The day before he went to the Heavitree Picnic in the Park and talked to endless people,  went for a blast down between Ludwell Valley and Burnthouse lane, met loads more people, some of whom fed me burgers and Obama salad.
The day before we just stooged around town, went to the pub and stood right under the railway line as express trains roared over. Then down to the river for a good canter and home again.
Today we will be doing row crop work on Exeter Community Agriculture's plot.
Obama gets variety, and that in itself is a reward. He goes faster and keener away from home, looking for new experiences, than coming back to the field he knows.
I let him graze the verges wherever we go, so he has an incredible variety of plant life as food, but that doesn't stop him tipping over bins to get at MacDonalds chips, which he adores, possibly in recognition of Temple Grandin's really impressive work with MacDonalds. He will scrape chewing gum off the roads with his teeth and anyone who says "Isn't he sweet" is expected to provide at least five minutes of scratching.
Variety is a reward. Leading your animal out is a reward, but it is also education, from the Latin Ex ducere, to lead out. So eductaion becomes a reward, not the reptitive learning of limited and stylised moves in a "school", but new experiences.
Archery is Obama's latest lesson. If you want to pick an animal to teach chariot borne archery to, Obama is a lot less than ideal. Bows are long stick like things. Obama, at some stage in his life, has been shown what a whip can do. The damn things terrify him. So I want to take a long whip like object and use it while driving him.
The obvious answer is blinkers, but I tend to agree with Black Beauty that they are dangerous fashion accessories. So i am going to have to teach him to accept the bow and arrows. I won't teach him to accept whips. I expect him to kick anyone who approaches him with a whip, and I will give him a carrot for doing so, or even some chips.
Yesterday with Charlotte and Danielle, he started really scared as the bow was assembled, but by the end, he was nuzzling the bow because he had learned that that got him turnip. Later on when I want to hit targets, I am going to have a major problem with him nuzzling the bow at the critical moment. But if I can get a novice to drive him cross country, solo, shooting a bow, I will be pleased.
And yes I will get all smug and tell you all on Facebook, but I deserve a reward. Obama will get a lot of turnip, carrots, radish, banana or whatever, but most importantly it will add another variation into his already varied life.
The reward is the variety. Just carrots works, but variety really gets Obama motivated. As a nomadic species, they rarely wake up to the same view.  New things are scary, but if you don't investigate and welcome the new, you couldn't be nomadic. Ponies are programmed to explore new places, new food, new sights and smells. They are always on the lookout for danger, but that is true wherever they are.
Thee simplest reward is taking them out somewhere new, leading them out, ex ducere, educating them.