The fact that the problem didn't mention any restriction about the shape of the poultry farm, it is safe to assume that its shape is rectangle. To determine the width, we have to calculate the total area first. If each hen has to occupy 4 square feet of flooring, then the minimum area for all of the 20 hens is: 4 × 20 = 80 square feet.
Next, we use the formula for the area of a rectangle: A = LW, where L is length and W is width. Substituting all known values,
80 = 12W
W = 80/12
W = 6.67 feet
Thus, the man should construct a farm that is 6.67 feet wide.
