_Cleaning and Bedding the Pens._ Careful attention must be given to keeping the pens and the ducklings themselves clean if they are to do well. Therefore the pens must be cleaned out as often as may be necessary to accomplish this purpose. The judgment of the brooder man must decide how often this is necessary but it will be at least once a week. When cleaning the pens the old bedding is thrown out from the front pens through the windows and from the back pens through the door provided in the rear wall for this purpose. Bedding the pens must be done more frequently, usually about every other day. Fresh bedding will help to absorb the droppings and will keep the pens from becoming sloppy or sticky. For bedding, straw, meadow hay, swale hay or any other suitable material available should be utilized. _Ventilation._ Plenty of ventilation is required in the brooder house in order to take out the ammonia odor which arises from the droppings. Properly managed, the doors and windows provide sufficient means of ventilation but some duck growers prefer to have roof ventilators in addition. _Other Types of Brooder Houses._ Many other types of brooder houses are used, some of them being shed roof construction and many of them being built narrower than this house, that is to say, 14, 16 or 18 feet wide with an alleyway along the front or rear side of the house from which the work is done. The hovers are placed at the back of the pens when the alley-way is in the front, otherwise, they are placed next to the alley-way. The disadvantages of these houses are that only single pens are provided and that valuable brooding space is used up by the alley-way. The advantages of the house described above lie in the fact that the hovers are in the center of the house with the pens on each side of this, thus doubling the capacity, and that by making use of a walk over the hover pipe no room is wasted in an alley-way. Having pens on each side also lessens the labor of taking care of the ducklings to some extent as the arrangement is more compact. Length of Time in Brooder _In House No. 1._ As a rule the ducklings are kept in the No. 1 house until they are from 2 to 3 weeks old, this of course depending somewhat upon the time of year and the weather and also upon the number of ducklings for which accommodations must be provided at any particular time. As the ducks are moved down through the house and eventually reach the last pens they are taken from this house and placed in brooder house No. 2. _Brooder House No. 2._ This is a heated house like brooder house No. 1 but in which it is not necessary to maintain so high a temperature. Sufficient heating apparatus should be installed to make it possible to maintain the temperature at 60 degrees if this becomes necessary in the early spring.