How to Tell a Horse's Age by Its Teeth (with Pictures) - wikiHow
Galvayne's groove and the presence of a hook on the upper corner incisors are poor indicators of age in horse teeth | Semantic Scholar
Aging Horses by Their Teeth | USU
I saw a very good example of a seven year hook on a corner incisor today. Please note that hooks in this location are commonly found at 7 or 13 years old
Aging Horses by Their Teeth | USU
Aging Horses by Their Teeth | USU
Aging Your Horse - Who knew teeth would give it away? - saddleupcolorado
Equine Dentistry - Honors in Equine Science
How To Tell Your Horse's Age By Their Teeth. – Irish Sport Horse Magazine