Another method, and one that is less expensive and quite effective as long as kept in good repair, is shown in Figure 8. Wire netting should be carried around the entire crib to a height of 2 feet or more from the top of the foundation. A strip of galvanized iron 8 inches wide should be fastened above the wire netting. The joints between the foundation and netting and between the netting and metal strip must be tight. As rats are unable to gain a footing on the smooth metal and can not climb over it, it is unnecessary to use wire netting above the strip. Care should be taken to join the lengths of metal tightly and to carry the wire netting and strips of metal across and around both sides of doors and door jambs. It is also advisable to provide doors with springs or weights to insure their remaining closed. [Illustration: B31365 Figure 9.--An inexpensive method of rat proofing a corncrib. It is supported by glazed tiles capped with galvanized washtubs, which, though not attractive in appearance, have successfully kept out rats] If possible the corncrib should have a concrete foundation and floor, as illustrated. Otherwise it should be elevated on posts or piers so that it will have a clearance underneath of feet or more. If the supporting posts or piers are covered with sheet metal, or are protected at the top with metal collars or disks extending at least 9 inches out from the posts, rats will be kept out of the crib. Old cribs can often be rat proofed in this manner at little expense. Dish pans and washtubs make convenient rat guards. (Fig. 9.) It is important that the area beneath the corncrib be kept clear and that nothing that the rats can climb be leaned against it.[1] [1] Plans for a 2,000-bushel corncrib (design No. 521) are available upon request addressed to the Bureau of Public Roads, U. S. Department of Agriculture, Washington, D. C. GRANARIES The rat proofing of granaries is of great importance, because of the abundance of food stored there and the corresponding opportunity for serious loss. The granary with concrete foundation and floors, tight-fitting doors, and screened ventilators presents no unusual problem, except possibly in connection with the elevator pit, which should be carefully checked against possible means of ingress for rats. Small wooden and portable granaries should be protected with wire netting. (Fig. 10.) Concrete feeding floors, troughs (fig. 11), water tanks, hog wallows, and similar structures should be constructed with a curtain wall, or apron, around the outer edge extending 2 feet or more into the ground (fig. 12) to keep the rats from burrowing underneath the slab. This also tends to prevent the heaving caused by frost and the uneven settling of the structure in soft ground. [Illustration: Figure 10.--Recommended method of rat proofing a portable granary] POULTRY HOUSES