342 POULTRY CULTURE 



When a stock of poultry becomes badly infested with worms, the 

 numbers of the parasites which may simultaneously attack a strong 

 bird may be so great that its strength is of little advantage. In 

 such cases it is advisable to kill off all stock and keep no poultry 

 on the land for several years. Stock from a badly infected flock, 

 if taken to new land, carries the worms with it. 



External parasites. Lice are often referred to as enemies against 

 which the poultry keeper must wage unremitting warfare. This 

 view exaggerates the importance of direct personal efforts to keep 

 these parasites in subjection. There are two general classes of lice, 

 — those which live upon the birds and those which only feed upon 

 them, remaining at other times in crevices about the roosts and 

 nests. Neither kind does perceptible damage when present in 

 small numbers, or multiplies too rapidly on adult birds when sani- 

 tary conditions are good, when the birds are vigorous, and when 

 ample opportunity is given them to " dust " themselves. Some live 

 on dead skin and feather particles. Very few birds are absolutely 

 free from lice, even when treated regularly with insecticides. 



The presence of lice in small numbers on the bodies of poultry 

 is by some authorities considered beneficial. They rarely become 

 seriously detrimental to any strong stock kept under favorable con- 

 ditions. Treatment for them should be necessary only on incubat- 

 ing poultry, on young birds when very small, and on old ones when 

 confined without opportunity to free themselves from lice. Con- 

 tinued necessity for fighting lice shows plainly that some other con- 

 dition needs attention. It may be the vitality of the stock ; it may 

 be the sanitary conditions ; it may be that, once allowed to establish 

 themselves, the lice, though constantly fought, have never been 

 effectively treated (this is the case especially with red mites, which 

 secrete themselves about the roosts). For lice on poultry, dry insec- 

 ticides (powdered) are used ; for lice about roosts, nests, and 

 buildings, liquid insecticides are applied freely to infested places. 



Vices. The bad habits of poultry are developed almost wholly in 

 close confinement under unsatisfactory conditions. Feather eating, 

 egg eating, and various forms of cannibalism common among 

 closely confined poultry are rarely seen among poultry at liberty 

 amid favorable surroundings, and give comparatively little trouble 

 among closely confined birds if the conditions are sanitary and the 



