Radioisotopes are the best method for determining absolute age, except when dates are chiseled in manufactured rock by reliable sources for which there is a well established provenance. The absolute...
Every age is a good age for a horse as long as he has a loving, caring human. With better medicines and vet care horses are living longer, healthier lives. Horses are now living into their 30's and...
Age for breeding - Most mares are able to be breed from their first "heat" cycle, about 18 months of age, up until they no longer have "regular" cycles. Most breeders like to start at age four...
Well, for an inexperienced rider, you would want to buy an older horse (probably 8 or older, well trained). If you are very experienced and are able to train a horse, you could buy a green horse...