Classic Roan (RO), also known as True Roan or Dark Headed Roan, is the most well known type of roan. Classic roan is dominant and thus cannot skip generations. The head and points of a classic roan are not roaned and retain the pony's color. Any color can be roan as roan puts itself over the pony's color. Roans often go through seasonal changes and some roans darken with age. Foals will usually not appear to be roan until they are several months old. Roans often develop patches of solid hair where there has been a scratch or injury, these are known as corn spots.
Another type of roan is Frosty Roan. The mane and tail of frosty roans are mixed with white hairs and some of have white hairs on the face. It is not known if Frosty Roan is a different mutation from classic roan, if it is a variant of classic roan, or if it is the result of an unknown modifier.
The mutation for roan has not been identified, however it is known which chromosome roan resides on. A zygosity test is available which can determine whether a roan is homozygous or not.
Classic roan is extinct in the Chincoteague Pony. The last known roan Chincoteague died 2008, the feral mare Strawberry Lady. One source stated that a chestnut roan stallion from Farnley Farm was sent to Chincoteague for three years and was bred to mares and that is likely how classic roan was introduced. The last three classic roans in the feral Virginia herd were all mares: chestnut roan A Touch of Dust, bay roan Rags to Riches, and chestnut roan Strawberry Lady. It also appears to have died out in the Maryland feral herd. Classic roan may however still exist in private hands as the descendant of one of the three mares.
Grey (G) is a modifier that depigments a horse's body color until it reaches near white. Grey is dominant, and thus cannot skip generations. Greys are born a color and through their lifetime "grey out", and subsequently go through many different graying phases. The speed at which a horse greys out varies. Dapple grey, rose, grey, white grey, steel grey, etc. are all names for stages of greying. Fleabitten greys have small dark flecks on a white coat and bloodmarks are a concentration of fleabits. White greys are often mistaken for true white horses. Greys have dark skin and dark eyes. There is a test available for grey.
Grey is currently not found in Chincoteagues. While there has not been conclusive evidence of a grey Chincoteague, the grey Arabian stallion Skowreym was loaned to the Chincoteague Volunteer Fire Department for two years in the 1960's so it is very likely some of his foals were grey. A postcard likely from that era with a picture of probable greys has also been found.
Grey may have also existed in the early days of the breed. A 1891 article in the New York City newspaper The Sun stated that the ponies "are most frequently black, gray, sorrel, or dun." However, Leonard D. Sale wrote in 1896 in The Horse Review of Chicago that, "I have never yet seen a grey, piebald, dun, or yellow purely bred island pony." A 1923 St. Petersburg Times article described the ponies as "bay, gray, dun, black, and sorrel".
Frame (O), also known as frame overo or just overo, is a pinto pattern. Frame is dominant, and thus cannot skip generations, and only exists in heterozygous form. Homozygous frames suffer from Overo Lethal White Syndrome (OLWS) and are known as Lethal Whites; such foals are born all white and die soon after birth due to an incomplete lower colon. Due to OWLS two frames should never be bred together. Frames generally have dark legs, the white is concentrated on the side of the pony, and have a white face. There is a test available for frame, the same which tests for OLWS.
Frame appears to have existed in the wild herd at some point in the past. It is no longer present in Chincoteagues. It likely would have been introduced through Mustang outcrossing.