That might work, but your guineas could decide it makes a wonderful place to take a dust bath instead. I've found that guineas like to have something over their heads when choosing a place to lay their eggs. They like to make nests under shrubs or small evergreen trees or beneath the weeds that grow in forested areas. I've also found nests tucked next to stone walls, especially in places beneath where one of the rocks in the wall sticks out. Eventually my hens' favorite nest was the area inside the coop under the nesting boxes built for our chickens. The nesting boxes were the perfect overhead protection that they felt comfortable with.