Age and Gender Depending Growth of Feathers and Feather-Free Body in Modern Fast Growing Meat-Type Chickens

Abstract

Two growth experiments with fast growing meat type chickens (Ross 308) were conducted to assess the growth of feathers and feather-free body dependent on age and gender (male:female ratio = 1:1). Birds were reared under uniform management and feeding conditions (floor pens; 15 pens per gender; 5 birds per pen) during the starter (day 1 to 22) and grower period (day 22 to 36). Diets were based on corn, wheat, soybean meal, soybean protein concentrate and balanced with feed amino acids to ensure an equal feed protein quality close to the ideal amino acid ratio by a constant mixture of the feed proteins. At start of the experiment and further on weekly up to the end of the 5 th week, 15 birds per gender (each 3 pens of 5 birds) were selected and 24 h fasted before quantitative de-feathering. Both feather and feather free body fractions were significantly increased with increasing age of the birds (p < 0.001). Feather percentage as related to the empty body weight increased non-linearly from approximately 2% at the end of the first week to about 4% at the end of the experiment. Feather percentage and dry matter content of the feather-free body was significantly higher in female birds (p < 0.001) as compared to males. Further investigations will show how this varying proportions impact on nutrient deposition of modern meat-type chickens dependent on age and gender, respectively.

Age and Gender Dependent Nutrient Composition of Feather and Feather-Free Body Fractions in Meat-Type Chickens

“…The study utilized a total of 180 growing broiler chickens (male to female birds = 1:1) and the methodical background as described in detail in a previous publication [7].…”

“…At next day (d1) averaged weighed birds were randomly allotted to 15 pens per gender (each 5 birds per pen) and kept under uniform management and feeding conditions (starter period: 1 to 22 d; grower period: 22 to 36 d). Further details were reported elsewhere [7].…”

“…Both the starter and grower diet [7] was based on corn, wheat and soybean meal, soybean protein concentrate and crystalline feed amino acids as main ingredients. Diet formulation aimed to meet current recommendations and was adjusted close to the ideal amino acid ratios.…”

“…According to animal welfare regulations, these birds were subsequently euthanized by CO 2 inhalation. Each sample of quantitatively collected feathers and of feather-free empty body was separately stored in plastic bags at −20˚C for further processing as previously described in detail [7].…”

“…Mostly, de-feathered carcasses were analyzed. The present study aimed to provide actual results about age-dependent changes in whole body composition based on analyzed feathers and feather-free bodies from male and female modern meat-type chicken, making use of a recently reported database [7].…”