Both nag and hackney continue to be used as synonymous terms. Frequent mention is made of hackneys and trotters in old farm accounts of the 14th century.
The first noteworthy trotting hackney stallion, of the modern type, was a horse foaled about 1755, and known as the Schales, Shields or Shales horse, and most of the recognized hackneys of to-day trace back to him.
The breeding of hackneys is extensively pursued in the counties of Norfolk, Cambridge, Huntingdon, Lincoln and York, and in the showyard competitions a keen but friendly rivalry is usually to be noticed between the hackney-breeding farmers of Norfolk and Yorkshire.
