Directions:Complete the following passage by using the words in the box. Each word can only be used once. Note that there is one word more than you need.
A. dip B. common C. desired D. addition E. embarrassing
F. carefully G. muddy H. fed I. access J. raising K. benefit
Ducks offer certain advantages over hens. Ducks are immune to some 41
diseases found in hens. Some breeds of duck produce bigger eggs than hens. In 42 , ducks lay eggs over a longer season than hens do.
Poultry(禽类) keepers with gardens have less to worry about if they keep ducks rather than hens because the former are unlikely to dig up plants and destroy roots. While both hens and ducks 43 the garden by eating pests, hens are known to damage grass beds. Ducks, on the other hand, will search for insects more 44 . Only very delicate plants are at risk from the broad, webbed feet of ducks.
Like all waterbirds, ducks need 45 to water, and duck keepers typically provide this by building a pond. Something this large is not absolutely necessary, however, ducks need only to be able to 46 their heads in the water to keep their nose clean. If a pond is provided, though, it is important to keep baby ducks away from it until they are old enough to put up with the cool temperature of the water.
When 47 ducks, one has to consider just how many the land will support. The rule is generallyabout 100 ducks per acre. If more than this proportion is introduced, there is a risk of pressing the soil, which can lead to 48 conditions for long periods as the rain is not easily absorbed into the ground.
While ducks offer many advantages over hens, they must be given a greater quantity of food, especially if regular eggs are 49 . An adult duck will eat between 170 to 200 grams of food a day. If the ducks live near grass and a pond, they will be able to find for themselves approximately 70% of their daily dietary requirements in warmer months but less than half that in colder times. Therefore, it is important that they be 50 on
enough food, such as grain, every day.