Feed Utilization in Growing Chickens in Relation to Shank Length

Efficiency of Feed Utilization in New Hampshires to Ten Weeks

“…Titus and Hendricks (1930), Hammond and Marsden (1938), showed that growth was a function of cumulative feed consumption. Glazener and Jull (1946) studied growth as a function of cumulative feed consumption in two strains of New Hampshires and Barred Plymouth Rocks. The equation, Y = a-\-bX was used; the constants "a" and "b" were solved by means of the least squares method.…”

“…, Hammond, Hendricks, and Titus (1938), and Hammond and Marsden (1938) applied the law of diminishing increment in efficiency studies in ducklings, chickens, and turkeys, and found that the relation between live weight and feed consumption was expressible by the law of diminishing increment in the three classes of poultry. Hess, Byerly, and Jull (1941) and Glazener and Jull (1946), in studies of feed utilization in Barred Plymouth Rock and crossbred broilers and two strains of New Hampsbires, respectively, used the formulae E = C-kW; which is a derivative of the equation for the curve of diminishing increment. In this equation, E was calculated by the formulae gain for the period --:…”

“…The data strongly suggest that the efficiency of feed utilization is inherited. Glazener and Jull (1946) studied efficiency of feed utilization in two strains of New Hampshires and Barred Plymouth Rocks and found that the progeny of the long-shanked strains tended to grow faster and utilize feed more efficiently than the progeny of the short-shanked strains. Differences in rate of growth among strains have also been observed by other workers.…”

Problems in Poultry Meat Production in the Pacific Northwest

“…In poultry meat production there exist nonproportional outputs per unit input throughout the growing period. Jull and Titus (1928), Hendricks (1931), Asmundson and Lerner (1933), Titus (1931, 1932), Titus, Jull and Hendricks (1934), Hess, Byerly and Jull (1941), Brody (1945), Glasener and Jull (1946), McCartney and Jull (1948) recognized the existence of the diminishing increment in poultry meat production. In general, poultrymen do not think in terms of the value of the marginal (incremental) output and cost; nor does the industry guide production or educate poultrymen in these marginal concepts.…”

Factors influencing the efficiency of strain comparisons in random sample testing of meat-type chickens

“…Hess et al (1941) demonstrated dif ferences among strains and crosses; Glazener and Jull (1946) reported differences between long and short-shanked progeny of two different breeds; McCartney and Jull (1948) found differ ences between two strains of Mew Hampshires, and Hess and Jull (1948) found significant differences among individuals, sexes and breeds as well as between crossbred and purebred progeny of the same male. From a study involving four breeds Fox and Bohren (1954) concluded that feed efficiency differences be tween sexes and between breeds are primarily a reflection of growth differences and that little would be gained by select ing for feed efficiency in addition to growth rate.…”