Osteoporosis, a progressive decrease in mineralised structural bone, causes 20 to 35 per cent of all mortalities in caged White Leghorn hens, according to S.A. Enneking of Purdue University.

Reporting in Poultry Science with co-authors from USDA-Agricultural Research Service, Livestock Behavior Research Unit, North Carolina A&T State University and the University of Illinois, they state that previous research has focused on manipulating the egg laying environment to improve skeletal health, with little research on the pullet.

The objective of the current study was to determine the effect of perch access on pullet health, bone mineralisation, muscle deposition and stress in caged White Leghorns.

From 0 to 17 weeks of age, half of the birds were placed in cages with two round metal perches, while the other half did not have perches (controls).

Bone mineralization and bone size traits were determined in the tibia, femur, sternum, humerus, ulna, radius and phalange (III carpometacarpal) using dual energy x-ray absorptiometry. Muscle weights were obtained for the breast and left leg (drum and thigh). A sample of pullets from each cage was evaluated for foot health, bodyweight, right adrenal weight and packed cell volume. Most measurements were taken at three, six and 12 weeks of age.

Access to perches did not affect breast muscle weight, percentage breast muscle, percentage leg muscle, bone mineral density, bone length, bone width, adrenal weight, packed cell volume or hyperkeratosis of the foot-pad and toes.

There were no differences in bodyweight, bone mineral content and leg muscle weight at three and six weeks of age. However, at 12 weeks of age, bodyweight (P=0.025), bone mineral content of the tibia, sternum and humerus (P=0.015) and the left leg muscle weight (P=0.006) were higher in pullets with access to perches than in the controls.

Enneking and co-authors say their results suggest that perch access has beneficial effects on pullet health by stimulating leg muscle deposition and increasing the mineral content of certain bones without causing a concomitant decrease in bone mineral density.

Reference

^{Enneking S.A., H.W. Cheng, K.Y. Jefferson-Moore, M.E. Einstein, D.A. Rubin and P.Y. Hester. 2012. Early access to perches in caged White Leghorn pullets. Poult. Sci. 91(9):2114-2120. doi: 10.3382/ps.2012-02328}

September 2012