Density and group size effects on caged hens of two genetic stocks differing in escape and avoidance behavior.

Hens of two moderately inbred White Leghorn stocks, known to differ significantly in escape and avoidance behavior, were compared for productivity traits, nervousness, and feather loss when housed four or eight per cage at densities of 348 (high), 464 (medium), and 580 (low) cm2/bird. Differences were found between stocks in sexual maturity, egg production traits, body weights, nervousness, and feather loss. The more nervous strain lost more feathers. Highest density housing depressed performance and increased nervousness and feather loss, but differences were generally lacking between the medium and lowest density housing. Group size effects were not detected for productivity traits, but hens kept in groups of eight had increased nervousness and feather loss. No interactions were detected between stocks and density, stocks and group size, or density and group size.