Colours

Bay - Bay horses come in a variety of reddish-brown hues, and are distinguished by black points (mane, tail, legs, ears, knees, hocks, or any combination thereof).  If there are white markings on the legs, there will usually be black above the markings.  
Light Bay horses may seem to resemble chestnuts in some cases, but the distinguising difference will be the presence of black points.

Black - the entire coat, including the muzzle, flanks, and legs, must be black with the exception of white markings.  If any doubt arises between black and dark bay, black can be determined by noting the fine black hair on the muzzle.

Chestnut - Body colour varies from light yellow to dark liver in colour.  Sorrel may have flaxen mane and tail, but usually mane and tail are the same colour as the body.   Will not have black mane or tail, but may have some black hairs in mane or tail.
Chestnut foals often have light blonde baby hair on their legs.  This hair should not be confused with true white markings. If you are not sure, wet down the hair and look for pink skin. 
The rule of genetics followed by CPAR is that the mating of two chestnuts always results in a chestnut foal.

Grey - Generally, a mixture of white and darker hairs growing out of dark skin, usually born solid or almost solik, colouring becoming lighter with age.  Markings can be determined ona grey animal by detecting the pink colouring of the skin. 
The rule of genetics followed by CPAR is that a foal will not turn grey unless at least one parent is grey.

Palomino - body colour is golden yellow, mane and tail are white.

Dun - Includes Bay dun, Red dun or Blue dun (Grullo). Body colour is usually yellowish, tan or greyish-gold. Faces, legs, manes and tails are often darker than the body, in the colour of the non-dilute coat (chestnut, bay or black). Often have a dorsal stripe, zebra stripes on legs and/or a transverse stripe over withers. 

Buckskin - A type of dun with body colour a creamy yellow or gold.  Mane, tail and lower legs are usually black.  May have a dorsal stripe and/or zebra stripes.

Coat Patterns

*NOTE: When registering a horse with white markings on any part of the neck, body and/or legs above the knees or hocks,  photographs clearly showing all markings must accompany the registration application.

Tobiano - Dark head, white legs, clearly defined markings.  Dark and white over the back.

Overo - Bald face, dark legs, splashy markings. Dark over the back. 

Blanket - Horses with a solid whit area, normally over the hips and may extend to the withers.   May have spots within the white area.

Roan - A roan is defined for registration purposes as a horse with approximately a 50% mixture of white hairs throughout a chestnut, bay or black coat.  Unlike greys, they do not dapple or progressively lighten in colour. Most roans have a dark head, whereas foals which are greying will first show grey hairs on the head.