Effects of Force-Molting by Conventional and Experimental Light Restriction Methods on Performance and Agonistic Behavior of Hens

Abstract

We conducted two experiments to compare the effects of force-molting on performance and agonistic behavior of White Leghorn hens. Treatments in Experiment 1 were 1) stress period (no feed and 8 hr light/day for 10 days) followed by recovery period (ground corn and 8 hr light/day for 18 days) and 2) same as Treatment 1 except that ground corn was supplemented with the amino acids cystine, glycine, serine, and threonine. Experiment 2 consisted of two treatments: 1) same as Treatment 1 of Experiment 1 and 2) stress period (cracked corn and no light for 10 days) followed by recovery period (same as Treatment 1; Experiment 1). In both experiments the hens were given 14 hr light/day and were fed a 17% protein layer mash during the premolt and postmolt periods. Nonmolted hens served as controls in both experiments. Force-molted hens fed ground corn supplemented with amino acids during the recovery period did not have significantly better egg production, egg weight, or egg quality than hens fed ground corn only. Force-molting by total light restriction was generally not superior to a conventional method (feed and partial light restriction) of force-molting, although hens force-molted by total light restriction did produce significantly heavier eggs (P <.05) than hens force-molted by a conventional method (67.6 g vs. 65.5 g). Force-molted hens performed significantly more agonistic acts per 10-min observation during the 18-day recovery period than did hens not force-molted. Data suggest that the social inertia (peck-order stability) of a small flock can withstand the pressures of a force-molt.