One of the most common faults with most poultry houses is the matter of ventilation. When poultry raising was first looked upon as a promising business, many men erected houses containing a large proportion of glass. It was thought that the sunshine was the only necessary feature for the birds under winter conditions, and they made their chicken houses veritable hot houses. But the results were not as had been anticipated. It was found that while the houses were fairly warm in the day time, they cooled off considerable at night, and poor results were obtained from this wide range between the day temperature and the night temperature. Then another step was taken by these pioneers. They decided to heat their houses artificially. But even this system did not bring forth the big yield of eggs that had been hoped for. In all this expensive procedure, a very important element had been overlooked, and that was the matter of fresh air. About twenty years ago, there was devised a poultry house that was a radical departure from this previous type of house. It was called the open front house, and gave surprisingly good results, where all previous types had failed, as regards egg production. This house was constructed briefly as follows: It was of the shed roof type; that is, had just one slant in the roof, the highest pitch being in front, and the lowest pitch in the rear. It had plenty of window light in the front side, about half of the south side, or front, being devoted to windows. The rest of the front was left open, save for a thin muslin curtain to cover the open space during bad weather. These curtains were tacked to wooden frames, and swung on hinges, so that they could be swung in to cover the open space at will. The most remarkable thing about the system was that the hens began to lay eggs, when proper feeding was obtained. Later, this led to the conclusion, now generally accepted, that the birds can stand considerable cold, providing it is not a damp cold, and that the temperature of the house is considerably more uniform between night and day than was the case with the glass house.