To calculate the density of horses per acre on the farm, you can use the formula:
\[ \text{Density} = \frac{\text{Number of Horses}}{\text{Number of Acres}} \]
In this case, the number of horses is 360 and the number of acres is 60. Plugging these values into the formula gives:
\[ \text{Density} = \frac{360 \text{ horses}}{60 \text{ acres}} = 6 \text{ horses per acre} \]
Therefore, the density of horses on the farm is 6 horses per acre.