Whipsnade turkey building a five ton nest . A new Guinea Brush Turkey , no bigger than a large hen , is building an incubator weighing about five tons at Whipsnade Zoo . The incubator is in the form of a mound 7ft to 10 ft high , with a circumference of anything up to 40 ft composed of decaying vegetation . In the top of the mound will be a crater , in which the female turkey will in due course lay her eggs . Once they are laid she will be driven away by her spouse , and the eggs will be duly covered with more decaying matter . The heat engendered in the pile will hatch the eggs . Photo shows , the turkey at work on his nest , which will not be completed until August . 13 April 1934