Chicken with eggs, thermogram footage. Thermography records the temperature of surfaces by detecting long-wavelength infrared radiation. The colours show variations in temperature. The scale runs from white (warmest), through yellow, orange, red and purple to blue (coldest). This footage shows the chicken's legs, face and eggs radiating the most heat (bright yellow). The chicken uses its body heat to keep the eggs warm, and the nesting material provides insulation to maintain the eggs at the required temperature for the chicken embryos to develop.