The aging process of horses on HR does not follow the normal pace of real life time. Horses become 1 month older every 32 real life hours. This is not tied to the care rollover at 03:00 HR time, instead the aging rollover for horses is at 24:00 (00:00). Because this check is every 24 hours and horses age every 32 hours, some days the horse will age 2 months instead of just 1 month.
Two important hallmarks in the aging process are the weaning at 6 months, and reaching adulthood at 3 years. It takes 8 days for a newborn foal to age to 6 months. Then it takes another 40 days for the foal to age to 3 years. In total, it takes 48 real life days for a newborn foal to reach adulthood. The last hallmark is at 25-30 years old at which point the horse may die of old (at the aging rollover). From the moment a horse is born, its lifetime will span at least 400 real life days.
Stages of Life
A newborn foal will stay by the side of its dam and doesn't require a stall of its own until it weans 6 months old (not related to the horse training exercise of weaning). During this initial phase of life, it is already possible to retire a foal, but it will continue to display by the dam's side until it weans. At 6 months old it will take up it's own stall and be shown separately from the dam. If you are at or over capacity with horses in your stalls, the foal will still age up and take up another stall, at the moment there is no cap going over capacity with newborn foals. However, you cannot purchase or catch new horses when over capacity.
A horse is a foal until they reach 3 years of age. Foals can only complete the four levels of basic training exercises. However, basic training is not restricted by age - you can still complete it after a horse has become an adult. A foal can also be entered in Conformation Shows, but it cannot be trained for or used in Competitions yet.
At 3 years of age, a foal will age up and become an adult. At this point, when it has completed all four basic training levels, you can choose which discipline for the horse to specialize in on the Training tab. This decision is permanent, once you have selected a discipline for a horse at this time it cannot be changed. After you have done so, you can have new training exercises for the horse and can enter the horse in Competitions.
Currently foals can only die prematurely from Overo Lethal White Syndrome, if a foal is born with two Frame Overo genes (OLW/OLW—as opposed to OLW/olw or olw/olw which are not affected by the syndrome themselves) it will be humanely euthanized immediately after being born. All other horses will die naturally from old age between ages 25 and 30 years; this is random chance and is checked at the aging rollover once a horse is 25 years or older. Right now there is no upper age limit for breeding and competing, and horses do not get any penalties for age or being pregnant.
Artwork & Coat Color
During the first 3 years of life, the foal artwork displays. There is no separate artwork for newborns or yearlings, or for fillies and colts of the same breed. Once the horse turns 3 years old, the adult artwork for its gender will display. This art will not change further regarding color or other details. Grey horses for example, will not progress in greying as the become older, instead they will have one image representing one of the greying stages their entire adult life. There is no separate artwork for elderly horses.
Some aspects of coat color are invisible on foals and only show up in the adult artwork, such as liver, rabicano, roan, and others. When buying a foal that is being advertised to carry such a color, double check the ancestors and genetic aspects of that color!
Some coat colors do show up on foals already. For example, the mane and tail of flaxen chestnut foals is visibly lighter than that of regular chestnuts. Grey foals show their normal coat colour, however it is darker or richer in colour than foals without grey and the foal will appear to have lighter hairs around their eyes and muzzle.
Speeding up the aging process can be done on the Summary tab of a horse. Horses can be aged in 6 month increments for 75 Delta Points for each aging.
Aging in this manner does NOT shorten the pregnancy duration for mares. If a pregnant mare is aged using DP, she will become older, but the time remaining for her pregnancy will not change at all.