_Cripples._ There will always be found in the flocks more or less crippled ducks and those with crooked backs, twisted wings, etc. As a rule ducks with twisted wings fatten well and are in good condition and can be killed about as soon as any of the others. The crippled ducks are sorted out into a lot by themselves where they are held until they can be put into condition to market. It is doubtful whether it pays the duck growers to bother with these ducks since they are rather difficult to condition and it would probably pay better to kill them. However, it is quite common practice to carry them until they can be marketed. _Cleaning the Yards._ The yards must be cleaned whenever they need it. It is a matter of judgment to decide when this is necessary but they must be cleaned whenever they get sticky or sloppy. The weather will have a considerable influence upon the frequency of cleaning which may be necessary once in two weeks, or in the yards of brooder houses Nos. 2 and 3 may run as often as once a week. In dry weather the yards are cleaned by sweeping up the droppings and carting them away. In wet weather the ducks in running about over the yard pack down the droppings until they form a sort of putty-like layer which has to be scraped off with a hoe. _Critical Period with Young Ducks._ The critical period with young ducks is the first week of their existence. With good management after they have passed this point not many are lost. The loss in young ducks from the time they are hatched until they are ready for market will range all the way from 5 to 30%. When the loss does not average more than 10% for the season this is considered good. Undoubtedly many duck raisers lose a greater percent than 10. [Illustration: FIG. 37. Yard ducks at rest. (_Photograph from the Bureau of Animal Industry. U. S. Department of Agriculture._)] [Illustration: FIG. 38. On this plant, the lay of the land was such that not all of the yards could be run down to the stream. So a shallow canal was dug from the stream through the yards which were without natural water frontage. (_Photograph from the Bureau of Animal Industry, U. S. Department of Agriculture._)] Disease Prevention Trouble from disease in young ducks is not severe although there is a greater loss from this source than in the case of mature ducks. The aim of the grower should be to use such methods of management and feeding as will keep the ducklings in good health and reduce the losses to a minimum. To accomplish this care must be taken to see that the brooding temperatures are correct, that the feed used contains what the ducklings need, that they are not overfed and that the house and yards are clean and dry and the feed and water dishes are clean. Remember that green feed and animal feed are essential ingredients in the ration.