In his famous essay, "On Thud and Blunder," Poul Anderson takes to task those writers of adventure fiction who treat horses as some sort of organic sportscar -- usually with a self-replenishing gas tank, at that. Admittedly, Anderson is not himself entirely accurate: he says that stallions are virtually unrideable, when historically they were often the prefered riding animal, beginning at least among the Hittites and classical Greeks (who used mares for chariots, but sometimes riding), and continuing among the knights of Europe. Even so, in historical fiction one often needs some sort of hard data on animals' abilities and requirements which is difficult to find all in one place. How far can your characters ride in a day without the horses being too pooped to continue at the same pace for weeks? How much feed do you have to pack to cross the Poison Wastes?
This will not attempt to consider equine behavior, training, or temperament, but it will help you figure just how many kitchen sinks you can put on one mule or pack horse; more often, just how many pack animals it will take to haul the pavilions, beds, hangings, chairs, chests, and such you need for a later camping scene. Consider the noise and disruption of such a pack train if your characters are supposed to be in the area unbeknownst to the inhabitants: you may have to scale back the luxury quite a bit. Also, it will cover food in and food out, and travel speeds.
To start, while a pony is often considered any non-Arabian horse under 14.2 hands, there are specific pony breeds which, pound for pound, are stronger than the horse breeds. This includes the most redoubtable Shetland pony, Welsh, Dartmoor and other English ponies, and Scandinavian breeds like the Norwegian Fiord and Icelandic ponies. Ponies are where it started: the horses on the Parthenon, galloping ahead of Pharaoh's or Agammemnon's chariot, or in sagas, are ponies by modern standards. Back then, you won't find the word pony in use because they were all horses. The generic pony is 9 to 14 hands at the withers (a hand is four inches) and 250 to 850 pounds.
Light horses are 14.2 to 17 hands tall, and include Arabians, quarterhorses, thoroughbreds, Morgans, jennets, standardbreds, and nags in general. Those sizes run proportionally 600-1200 pounds, averaging 900: remember this when some character picks up a horse to prove strength. Draft horses are over 17 hands and 1400 pounds, and again are stronger than standard horses. They are not "plow horses." Because of their weight, they would sink to the fetlocks in plowed fields. They were originally bred to the largest sizes as cart horses, but not as the destriers of armored knights; that is an outmoded fiction. The big plow horses of today are actually "draft chunks" bred of draft stallions and ordinary mares, about halfway between their parents in size and weight.
Also included here are asses, also called donkeys or burros. Often burro is used for the smaller types (about 300-400 pounds), donkey for the middle size (400-500 pounds) and ass for the largest breeds (500-600 pounds).
When asses are bred with horses, you get mules. Normally mules are sterile, but Herodotos reports two incidents of successful foaling by female mules (hinnies), Suetonius one, and in the 1980s there was one born named Blue Moon. Large draft mules are the size of small horses, but much stronger. Longears average 700 pounds body weight, but may range up to 800 pound draft mules.
Speaking historically, not of thoroughbred racing, horses at three are too young to ride, but can be trained to draw. They are usually trained to the saddle at four, considered prime at five, and old at twenty. They may live into their thirties, the maximum being a Methusalean fifty. In the heyday of Victorian horse abuse a cabhorse or carthorse might be completely broken down at twelve, fit only for slaughter.
When grazing horses, figure one to two acres per animal at a time, but they must be moved to new pasture as the manure builds up, every three to six months. A pony can do on a third the land. Horses eat only grass, no weeds. Asses will eat weeds, but never woody growth. Burros of the southwest chew cactus spines into harmlessness.
An idle horse has under two hours a day of exercise or work. Light work is two to three hours a day; medium work, four to five hours; heavy labour five to eight hours a day.
The daily ration per 100 pounds of horse (not per animal) is two pounds of really good hay for an idle animal; .5 lb grain and 1.25-1.5 pounds of hay for light work; 1 lb grain and 1-1.25 lb hay for medium labor; and a hard-working horse needs 1.25-1.33 lb of grain and 1 lb of hay per hundred pounds of body weight.
Breeding mares in the third of the pregnancy should have .5 to .75 pounds of grain per hundred pounds of body weight, plus hay or pasture like a regular horse; lactating mares, .75 to 1 lb. of grain per 100 lbs. Race horses need 1.5 lb of grain and 1.5 lb of good hay per 100 lbs in season. Rapidly growing foals that have been weaned should get 1.5 lb grain and .75 lb hay per 100 lbs.
This feed must be split into two to four feedings per day, not given all at once. The horse must be cooled down before eating, and allowed to digest for an hour, or severe, even fatal, indigestion will result.
This is one of the reasons horses were always a possession of the upper class, the equivalent of a luxury sports car, while common people rode asses and mules, which are both tougher and more intelligent. It is expensive and difficult to keep horses healthy. They require more leisure and more care. They will get violently, even fatally, ill if switched too quickly from hay and grain to green pasturage, too.
Proper grain mix would be 100% rolled oats, or 70% oats and 30% maize, or 70% oats, 25% barley, and 5% bran. Also, a horse needs 5 to 12 gallons of water a day and 2 to 3 ounces of salt per week, not day, depending on work load, animal size and outside temperature..
In the early 20th century, US Army daily forage rations were given as 12 lbs of oats and 14 lbs of hay per horse. Army mules got the same hay, but only 9 lbs of oats. This is about right for a 900 lb horse, the Army standard.
So for asses and mules, take the above horse feed figures and allow the same hay, but three-quarters the grain. Ponies often require no grain at all, only good hay and/or pasturage, unless they are heavily worked.
A three-wire bale often is over a hundred pounds. Two-wire bales of hay, at around 45 lbs, are handier for most people.
Figure a ton of hay takes 250 cubic feet in bales and a single horse requires three and a half tons of hay per year. In most times and places, there is only one time of year for making or buying hay, so you must figure storage for a year's worth.
As most animals, equines are a source of food. The meat is strongly flavored, sweeter than venison, and in those unused to it will produce diarrhea for a couple of days, as many a protracted seige has shown. About half the live weight of a healthy animal is edible meat; less, of course, on a starved animal.
Horsehair, from the mane and tail, ranges from six to fifteen inches. It is used for musical bows, and spins into strong cordage. It takes abrasion well, and a fine thread of it can be woven into the eternally enduring horsehair upholstery of Victorian furniture.
As milch animals, 600 Mongolian mares give a combined total of 25 gallons per day. A Baskirsky mare is expected to yield 2000 litres/440 gallons in seven to eight months of lactation. A Kazakh mare gives 20 litres per day. Lactation of course quits entirely during the year-long pregnancy, so those who depend on mare's milk need to rotate their freshening.
Invented only in the Middle Ages, no ancient or antique animal should be shod. They are often "lamed" by hard travel in the sense that the hoof is wearing away faster than it can be grown, so that a party must lay up for a couple of weeks while the hooves grow out.
Only animals that work on hard ground or roads need shoes to protect the hoof. Those that do not travel too hard, on soft ground or grassy fields or sand will not wear out the hoof (the animal's toenail) excessively. Sometimes an animal in draft work will be shod so that a cleated shoe will give it better traction on heavy drags. Another factor in shoeing is dampness: animals on damp pasture (like anywhere in England) will probably need shoes for hard work, because this softens the hoof, while a horse in the American Southwest may train for and compete in 100-mile endurance races without shoes.
Poor shoeing on a young animal will permanently deform the legs and carriage, resulting in cow-hocks, pigeon-toes, or splay feet. Sometimes, "gaited" horses will be given special shoes to make them prance higher.
As the hoof grows even when shod, the shoes must be changed every six to ten weeks. The hoof is shaped like the bottom of a cone, growing wider as it grows longer, and the shoe that fit several weeks ago will now be too small. Even if unshod, a horse's feed should be inspected regularly to remove excess growth or to level uneveness of wear or breakage.
Shoes are "thrown" when the heads of the nails holding on the shoe wear away, and the shoe slips free, partially or entirely. This occurs only when travelling so constantly as to put high mileage on a shoe before it is outgrown, or when waiting too long between shoeings -- they will wear out sometime.
There is nothing to stop a character from riding an ass, mule or draft horse. Draft horses are very wide-barrelled, and above a trot they galumph. Also, many of the breeds are not particularly bright, so that they can learn only the basics of being ridden. Asses and mules were formerly much more common than horses for all uses, because they were hardier and cheaper. Riding mules were preferred by many in the West, especially surveyors. However, neither are fashionable in the modern period, which is why horses now predominate where keeping equines has become a hobby, rather than a travel or work necessity.
The horse must not only be old enough to bear weight on its back, but be strong enough to carry the weight of rider and tack. Like humans, a horse's strength is often a function of its size, within a range. Thus, while a Shetland can trot uphill and down all day with a grown man on its back, it is likely to stagger to a halt under the same man armoured.
For children under eight, an animal of eleven hands is tall enough. Twelve to thirteen hands will suit a child up to ten. Early teen children will do on large ponies or small horses. Short people of whatever age need shorter animals so that the curve of the barrel will not be uncomfortable and so that they can mount unassisted. Short (4'11") dressage riders, after years of being put on the standard Euro-style 16 to 17 hands high warmbloods, have found blissful pleasure in moving to a horse actually sized better for them, like a 15 hh Andalusian. Also, it is difficult to saddle an animal too tall for you. When riding sidesaddle, barrel girth is no longer important, which is why Victorian damsels can use "men's horses" if only they can find a mounting block.
Of course, you can always ride a smaller animal that will bear the weight. The first ridden horses were pony-size.
The Middle Ages of Europe, despite its lack of scientific breeding, may have been the heyday of riding horse development. One begins with the war horse, the great horse or destrier which again was not a draft horse: they were prized for being tall and fast, not gigantic. They looked like today's heavy hunters of 15 to 16hh, not the Budweiser Clydesdales. A wide variety of palfreys were available according to their speed or smoothness of travel (someone here remembers an article on palfrey varieties in British History Illustrated magazine, from 1978 or thereabouts). For example, there was the palfrey ambloise, the smoothest riding, very suitable for pregnant women who had to travel. Some of the Medieval specialised gaits survived in the breeds of the American South, or were transferred to Central and South America during the Spanish Empire. The Spanish jennet -- Spanish breeds in general were highly aclaimed -- was swift and enduring, but unlike the Andalusian and Lusitano of today, which specialize in being light grey, the jennet was always a black horse.
With four rather than two feet, horses can move them in a variety of patterns at differnt speeds, called gaits. These include the three most common, also found in asses, mules, and zebras (another equine).
1) Walk: one foot at a time. This gait is used any time the animal is heavily burdened, or allowed its leisure. It is the normal gait for a horse, and can be kept up all day by an animal in any kind of hsape. When heavily burdened or exhausted, a horse, like you, takes shorter, slower steps, a slow trudge. A brisk walk was the speed at which medieval knights on their destriers hit the enemy line: the gallop was used only in jousting. Yes, many movies and old books describe them charging at a gallop, but that is an anachronism, due to thinking of them as modern cavalry, which does charge at the gallop.
2) Trot: a faster gait, where two diagonally opposite feet are moved while the other pair bear the weight. Rather bouncy, the rider usually will cope by shifting weight in the hips, cowboy style, or by posting, riding precisely with the bounce, lifting the body with the thigh muscles so as not to get slammed by the saddle. Posting is very tiring for the rider, but part of the European ramrod back school of equitation, and is both artificial and unnecessary. The Arabian breeds are notable for being able to trot all day. A fast trot is about 30 mi/hr.
3) Gallop: a three-beat run where only one hoof is down at any time. It can be easy and not too fast, then called a canter or gallop-in-hand, or a driving sprint for maximum speed, about 45 miles per hour in thoroughbred racing. It is always short-term. Horses, like most grazing animals, are designed to sprint away from an attack, then settle into a trot until their nerves settle, and go back to strolling and grazing. Human beings can run for hours, but this is one of our adaptations as predators.
Additionally, there are speciallized gaits, rarely found except in horses specially bred and/or trained.
4) Pace: with the same speed as a trot, the horse moves both left legs, then both right legs, rocking back and forth slightly. The Narragansett Pacers were notable for naturally preferring this gait to a trot. Pacers can show up in nearly any breed. All Age of the Horse writers recommend this to riders as being less strenuous than a trot (you don't have to post) so that you do not arrive at your destination "hot and mussed up" (Speed, 1910). A slow pace is called an amble. The palfrey ambloise was a pacer.
5) Rack: also known as single-foot or slow-gait, the smoothest gait of all, that can be done to the speed of a slow trot (5-7 mi/h). Showy high-stepping American Saddlebred/Kentucky Saddler horses are trained for this.
6) Running walk: also known as the fox-trot. Somewhere between a walk and a trot, this smooth gait is mentioned by pre-WWI authors, but often lumped with the rack by moderns (who see a lot fewer horses in a day). It may be considered a very fast rack without the high knee action, producing a speed of six to eight miles per hour. Tennessee Walker foals do this without training.
7) Paso: Peruvian Stepping horses naturally do the four-beat paso, averaging 11 mi/hr.
8) Marcha: between a trot and a canter. Done by the Mangalarga of Brazil, this rocking gait is not always pleasant, but natural and easy for the horse when one wants to make speed. Remember this when you are writing riding in gaucho country.
The Paso Fino of Puerto Rico, Peru, Columbia, and the Caribbean has three four-beat gaits, the slow paso fino, the steady, long-distance paso corto, and the faster paso largo.
Think of the pack horses as being ridden by the baggage, but controlled by a leader riding ahead, or a herder walking alongside. As wagonable roads were extremely rare before the later 1700's, pack trains are the normal means of moving goods overland in earlier ages. Medieval merchants usually did not travel to fairs with several wagons of merchandise, but with a score of pack mules or asses. A wagon would tend to indicate someone hauling a relatively short distance. Gypsies only adopted their caravans in the 1800s, thanks to road conditions.
Travelling through settled areas where feed is available and roads are moderate to good (for horses, not cars), a pack horse can carry a good quarter to a third of its weight at a walk for a ten-hour day.
Otherwise, you must figure the animals of your pack train as needing time to graze before and after a day's haul, and operating only off the lower calories of grass, unless part of their burden is their own feed. A wilderness pack-train's travel day is from about ten in the morning to four in the afternoon. This also allows time after dawn for the wranglers to find the animals where they have wandered in feeding. Unburdened but hobbled, this can be from a few yards to a couple of miles. A four o'clock halt for the day is usual enough for any back-country travelling, giving enough daylight to make camp.
For weeks on end, the average grass-fed pack horse (weighing about 900 lbs) can carry 140 to 180 lbs, or 15-20% of its weight. Mules are lighter but carry the same loads, or 20-26% of their body weight. Asses, ponies and draft horses carry in the same proportion as mules.
In mountains like the Rockies, pack trains of horses and/or mules may cover as little as five miles horizontal a day, though with good flat terrain and favorable weather they can make 25 mi/day. Figure fifteeen miles a day as an average speed if things are mixed or variable. Asses are slower, averaging 10-12 mi/day.
If everything is laid out ready, and nothing has to be hunted up, two experienced people can pack a horse with roped-on bundles in ten minutes. Figure a half-hour for most semi-skilled fumblers. The weight must be evenly distributed side-to-side, though fore-and-aft it is best to put more on the shoulders than the lower back. Panniers, boxes made to hold gear or cargo, one on each side, may be used to hold various supplies; figure a shape 22" long, 15" high, and sticking out 9" in brushy terrain, as much as 12" if trails allow the clearance. Panniers cut down ready time to what it would take to saddle the number of animals.
If you are packing supplies for travelers rather than hauling merchandise, figure one pack horse per person, as well as one riding horse. Otherwise, figure six or seven animals per wrangler in the wild, twice as many animals in settled zones.
Horses are depicted as draft animals earlier in history than they are shown being ridden. An animal that has been taught to draw can be broken to saddle, but it is more challenging to teach a saddle-broken animal to draw, as they read the resistance of the load as a command to stop.
Because of their great weight, draft horses require the solid footing of hard ground or roads. Lighter equines can, of course, pull lighter loads. Even a Shetland pony can pull its own weight in a wheeled cart fairly easily. They were much used in English coalmines begause they could move loads of coal much larger than themselves through the low tunnels. Even animals too young or weak to ride can draw a load. Plowing is draft work on very soft ground, so that in America the draft mule came to be preferred for the work.
Light horses can draw about 50% of their weight in a sledge, 100% in a wheeled vehicle on good road at an easy walk, 180% at a miserable trudge (note that the load includes the weight of any vehicle), 1000% on a railway track, and 6500% towing a waterborne barge from the shore. For other equines, they draw 60% in a sledge, 120% wheeled (220% at a trudge), 1200% on a railway, and 7800% in a barge.
With this mass of data, you should be able to figure how far your characters can expect to travel a day, how many animals they will need, and from this whether or not they will move unnoticed or leave titanic trail. You can delay characters through a sudden sickness among the barge-pulling canal mules, or make a mess of them by sticking them on hard-rocking mangalargas instead of gliding paso finos. Now you can figure just how many days of desert to throw at the riders, and still have them mounted at the end of it. Here's to good writing!