Grey horses come in a variety of different shades and types. All horses that have a grey gene will eventually begin to fade from their original base color over time, usually ending up with white hairs. However, not all grey horses turn to white and some will still have dapples or speckles of their original coat color. The different shades of grey are determined by genetics and the individual hairs themselves, rather than depigmentation of the skin or eyes (as it does in humans).
Foals are usually born with their base color and can only become grey as they grow older. There are two tell-tale signs that a foal will grow to be grey: if it’s father or mother is grey, and it has very dark lower legs. This is because the grey gene causes excess pigmentation in the first stages of development, so the lower legs are often darker than the body.
When a horse is young, it will be a solid or light grey shade depending on its parentage and if the grey gene is homozygous dominant (GG). Then, as the grey hairs start to form, they will have rings of dark hair that highlight the new white hairs that are starting to sprout out. These rings are the dapples that we are familiar with in grey horses and are known as “bloom dappling.” The colour of these rings will change throughout the year based on the season and may even disappear at times. Generally, dappling will be most prevalent in the younger grey horse – between two and seven years old.
As a grey horse grows older, it will continue to lighten until it becomes a palomino or cream colored shade. Some greys will even have the rare, splotchy appearance of the Flea Bit grey, which is caused by a mutation in the greying gene that creates re-pigmentation. The splotches will be small but dense and will appear on the chest, neck, shoulders, and head. Some of these horses will also have dapples around the eyes.
Iron grey is a classic grey shade that is dark and has a salt and pepper look to it. This is the stage that most people think of when they imagine a grey horse. Rose grey is a lighter shade that appears in the middle stages of greying. Mulberry grey is a stage where a bay or chestnut horse starts to go grey and their hair takes on a pinkish tinge.
Grey roan is a unique shade of grey that has a pattern of dapples or speckles in black or brown hairs that are intermixed with the light grey hairs. The dapples are usually ring shaped but can be splotchy in appearance as well. This shade of grey is typically found in roan breeds but can be seen in other breeds as well.