an average one,not big or small...
helping hint...before tractor and lorry,harvest was hauled from field with platform cart,one double horse platform could load 5 tones...then first french camion had 5 tones capacity...
Zardoz
Favorite Answer
The horse has resisted standardization.
From Wiki: Horsepower;
Horsepower from a horse
In 1993, R. D. Stevenson and R. J. Wassersug published an article calculating the upper limit to an animal's power output.[9] The peak power over a few seconds has been measured to be as high as 14.9 hp. However, Stevenson and Wassersug observe that for sustained activity, a work rate of about 1 hp per horse is consistent with agricultural advice from both 19th and 20th century sources.
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marc
1 HP obviously