There are nine rules of good feeding.  Each one is extremely important and applies to any horse, any breed, and any age.

1.  Feed little and often.  Horse's graze in their natural environment, never taking huge amounts of food at one time.  Feeding little and often helps replicate their natural habits.  It also keeps the stomach from getting too full at once, keeps the horse from adopting stress and boredom caused habits (cribbing, weaving etc.).

2.  Fresh water available at all times.  Just like people a large percentage of the horse is water (60 to 70%).  They need fresh water available at all times so that they can drink as they eat.  This prevents dehydration, helps in the asorbtion of nutrients, vitamins and minerals and aids in digestion. On an average day a horse will drink between 6 and 12 gallons of water.

3.  Feed good quality feed.  Feed good quality feed such as hay, cubes, oats etc.  The hay should be lush, green, with no dust,  mold or wetness.  Oats should be in the same condition.  This insures that the horse does not develop wind problems and does not get colic from poor feed.  It also insures that the horse maintains his weight as poor hay and oats does not give the nutrients and energy required by the horse for the same volume of good quality hay.

4.  Do not feed right before or after work. A horse should be given ample time to cool out after riding before being fed.  Feeding too soon when the horse is still hot, can lead to colic.  Feeding large amounts too soon before riding can lead to the full stomach pressing against the diaphragm giving wind problems.  It takes an average horse one and a half hours to digest it's feed enough for hard work.

5.  Feed at the same time each day.  Horse's are creatures of habit.  Feeding at the same time each day allows a pattern to be made.  This daily routine gives the horse something to count on, helping against the development of boredom and stress related habits.  It also allows plenty of time for digestion.  If you feed at 10 every morning two every afternoon and 8 every night you do not have to worry about feed not being cleaned up, not enough time before riding etc.  But if a sporadic feeding schedule is used the horse will find it hard to finish his rations for one feeding and then be left with none for too long after the next.

6.  Feed a succulent each day.  Horse's natural feed being grass lack certain things when fed just hay and concentrates.  Feeding something succulent (carrots, apples, grass etc.) helps replenish what is missing in the horse's feed.

7.  Feed according to the individual horse, it's work, age, temperament, and needs.  A 16 hand TB does not need the same feed amounts of a 15 hand QH when receiving the same amount of work.  The TB will often need more feed not only for it's added size but because TB's are often harder keepers, losing weight faster then most stock breeds.  At the same time a pleasure horse may never need to be fed concentrates while an event horse may need large amounts of them to keep up with the energy demands of the horse's discipline.  No matter what tailor each feeding routine to the horse.

8.  Make feed changes gradual.  Horse's have sensitive systems.  To prevent problems such as colic, indigestion changes should be done slowly.  When changing rations of feed do it a little each day.  Go say from a 1/4 gallon of oats a day to one third for a few days and then up to a half gallon a day.  This allows time for bacteria to form to break down the added amounts (or new feed) and can prevent digestion problems and colic.

9.  Feed adequate roughage.  It is the basis of the diet and keeps the digestion system healthy.  The bulk of a horse's daily ration of roughage should be fed at night when the horse has plenty of time to eat and digest it.

Oats:  The traditional concentrated feed it's one of the best all around concentrates.  Easily found and fed oat's store well and are not expensive to come by.  They can be fed whole, but preferably are rolled, bruised or "crimped" making for easier digestion.  But once crimped or bruised they should be fed with in a few weeks or they will go stale and lose their nutritional value.

Barely:  Rolled or crushed barely can replace part of the oats fed daily.  Barely should not be fed whole unless it is boiled.

Bran:  Bran is a good mild laxative.  it is also a good way to warm an ill horse.  Mixed with warm water, succulents, and/or barely.  Bran must be fed sparingly as it prevents asorbtion of calcium.

Linseed/flax:  Fed as a jelly or a gruel it is a good way to add weight to a thin horse and to add gloss to the coat.  To prepare take a cup full of seed and mix with 4 cups of water.  Soak for 24 hours then bring to a boil and simmer until the seeds split.  Let cool.  It will set into a jelly or a gruel (more watery).  Either way feed it mixed into the horse's normal feed making sure to get the water as this holds most of the nutritional value.

Beet Pulp:  Made from dried sugar beets beet pulp is a common addition to many feeding regimes.  It is high in fiber and in calcium.  It must be soaked in water until it is completely swollen.  If not it will swell in the stomach and cause colic.

Pelleted feed:  A good and easy way to feed horse's the pelleted feed can be found at most feed stores.  Sometimes called complete feed it combines many different feeds, added vitamins, minerals and nutrients.  It can provide what is needed to gain or maintain weight with out the hotness that oats and barely can cause.  Different formulas have been developed for young horses, adult horses, horse's in hard work, and pregnant and nursing mares.  Using these types of feed can guarantee what your horse is getting in it's feed with the easy to check labels with ingredients.

Succulents: help in providing what is missing in the horse's diet who lacks access to grass.  They also help improve appetite.

Succulents can be anything from apples to carrots just to hand grazing on grass. Efforts should be made on the part of the horse owner to provide succulents each day.

Roughage: is the bulk of the horse's diet. It is the main substitute for grass.

Hay:  should be sweet smelling, light green/brown in color throughout. Care must be made to only feed hay which is in good condition.  Mold, dust, and moisture can lead to many various health problems.

Alfalfa: is a richer hay containing a clover type plant.  Care should be taken care when feeding large amounts of it.  It is a good hay for adding weight to a horse. It can be fed mixed grass hay.

Hay Cubes:  A good alternative for horse's with wind problems hay cubes are vacuum packed and sterilized so that no mold, or dust is inside it is a much easier solution then soaking hay..  Also good for adding weight to a horse, used in conjunction with regular hay it can encourage horse's to eat more bulk then they normally would.

AM
7 pounds of hay fed outside in his turn out pen
2 pounds of oats

PM
7 pounds of hay fed when horse is brought in
2 pounds of oats

NIGHT
7 pounds of hay
 

The feed is given in pounds because with different feeds the weight is different.  7 pounds of hay is more flakes then 7 pounds of alfalfa cubes.  Same goes for concentrates, weight a lot less then oats, and less corn is needed to provide the same energy of oats.

As the horse's work increases the percentage of the feed that is concentrates should increase.  This gives the horse the added energy that is required for the work level while maintaining his weight.