at what age does a colt become fertile
- -- Dan. Most yearlings and 2-year-olds can and will breed under good circumstances. There's probably not a horse practice without a first-hand story of the pregnant filly that was only with a colt until a year of age.So for sure, many fairly young colts can be fertile.ow young is too young to breed a colt? We have a coming 2-year-old who acts like he is ready to breed. We don't have any horses to breed to him, but the question came up for discussion last night among a group of guys. This colt was out there showing his stuff along the fence near the fillies.