An experiment was conducted during three consecutive winters (1955–56, 1956–57, and 1957–58) to determine the effects of rigorous climatic conditions on egg production and feed consumption by laying hens.Two breeds of birds (White Leghorn and Barred Plymouth Rock) were housed in an unheated and a heated house.The results indicate no significant adverse effects of the colder house on egg production.The saving in feed consumption in the heated house did not make up for the added cost of heating, which amounted to $1.01 per bird.