A statistical evaluation of several coding systems used to determine the degree of infestation of the shaft louse, Menopon Gallinae (Linn.) on chickens

Abstract

An evaluation of several coding systems, or arbitrary sets of numbers, used to estimate louse populations on chickens was performed. Included in the study was the development of a technique for the removal of lice from chickens and technique for making actual louse counts.

The procedure involved consisted of coding, by 4 coding systems, the louse infestations on 79 individual chicken hens. Each chicken was then fumigated and the feathers fluffed to remove the lice after which counts were made using a stereomicroscope. The resulting numbers were subjected to several statistical tests which indicated that there are linear relationships between the numerical symbols and the infestations they arbitrarily represent. It was also found that due to the improper spacing values, the accuracy of one coding system was inferior to the other three systems.