. The diseases of poultry. DISKASMS (M'- IHirLTKY. 177 of lice which live upon thcni alone, and there are but comparatively few kinds of lice which live upon two or more species of birds. We may, consequently, favor the multiplication of lice by making the con- ditions favorable for them, but we can not prodvice lice where none exist. The conditions which favor the nudtiplication of lice and other external parasites are found partly in the 1)irds and partly in the surroundino;s. Unhealthy or unthrift}^ birds, or those which from any cause lack strength and vigor are most subject to the at- tac
. The diseases of poultry. DISKASMS (M'- IHirLTKY. 177 of lice which live upon thcni alone, and there are but comparatively few kinds of lice which live upon two or more species of birds. We may, consequently, favor the multiplication of lice by making the con- ditions favorable for them, but we can not prodvice lice where none exist. The conditions which favor the nudtiplication of lice and other external parasites are found partly in the 1)irds and partly in the surroundino;s. Unhealthy or unthrift}^ birds, or those which from any cause lack strength and vigor are most subject to the at- tacks of such i)arasites, and may be found literally covered with them when other members of the flock are comparatively free from their attacks. For similar rea- sons some varieties of birds are much more likely to be infested with vermin iinder the same con- ditions than are others. There rXiiAx.—Goitiodesdissim^iix. are birds so strong, healthy and vigorous that lice can not thrive u])on them. Exer- cise, proper feeding, pure air, all have a tendency to keep the birds in a condition unfavorable to the ex- istence of the parasites. On the other hand accumu- lations of manure and filth, close confinement of the birds, lack of dusting places, buildings with crevices in which the insects may hide, and damp, dark and badly ventilated houses are conditions which favor the parasites and lead to their rapid development. The twultrj^-yard may be kept practically free from these insect pests, but there is always a liability' of their introduction with ])urchased fowls or with ])irds. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Salmon, D. E. Washington, D. C. , G. E. Howard & co.
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Keywords: ., bookcentury1800, bookcollectionamer, bookdecade1890, bookyear1899
