# Effect of Density and Lineage on Dorsal Surface Temperature, Performance, and Carcass Condemnation of Broiler Grillers

## TL;DR

This study examines how bird density and lineage affect the temperature, performance, and carcass quality of broiler chickens raised in a Dark House system.

## Contribution

The study provides new insights into the combined effects of bird density and lineage on thermophysiological and performance indicators in broiler grillers.

## Key findings

- Dorsal surface temperature was influenced by age, time of day, lineage, and density.
- Higher bird density did not negatively impact mortality, weight gain, or carcass condemnation.
- Cobb and Ross lineages showed differences in carcass condemnation and temperature patterns.

## Abstract

Thermographic monitoring of the back surface of broiler grillers and the environment are accurate indicators of thermal comfort, allowing production to be enhanced and ensuring the quality of the final product. In this scenario, infrared thermography was used to evaluate chickens’ thermophysiological state related to bird density, lineage, age, and time of day, isolated or integrated, on dorsal surface temperature, performance and carcass condemnations of broiler grillers reared in a Dark House system. The main results revealed that the dorsal surface temperature in the broiler grillers was affected by the combined effects of age and time of day, lineage and density, and lineage and age. The increase in the density of broiler grillers did not negatively influence mortality, average daily weight gain, and carcass condemnation. However, partial condemnations and arthritis condemnations were influenced by the lineage.

The aims of this study were (i) to evaluate the effect of density, lineage, age, and time of day on dorsal surface temperature and (ii) to evaluate the effect of density and lineage on performance and carcass condemnations in broiler grillers. The evaluations were carried out in barns with the Dark House system, with two densities, 17 and 19 chickens/m2 and two lineages, Cobb and Ross. The dorsal surface temperature of the chickens was measured by infrared thermography at 7, 14, 21, 23, 25 and 27 days of age, four times a day. The average daily weight gain, feed conversion, mortality, partial carcass condemnations, as well as those due to arthritis and dermatosis were also evaluated. The highest dorsal surface temperatures were observed in Cobbs housed at a density of 17 chickens/m2, and in Ross housed at a density of 19 chickens/m2. Cobbs housed at a 17 chickens/m2 density showed the lowest feed conversion compared to Ross at the same density. Ross showed higher dorsal surface temperatures when compared to Cobbs at 14, 21, and 27 days. Cobbs showed higher percentages of partial carcass condemnation and arthritis compared to Ross. The higher density of broiler grillers in the Dark House system does not influence the dorsal surface temperature, performance, dermatosis, arthritis, and partial carcass condemnations.