Welfare of broiler chickens reared in two different industrial house types during the winter season in Southern Brazil

ABSTRACT

1. The following trial compared broiler chicken welfare in closed-sided (CS) versus open-sided (OS) industrial house types during the winter season in the South of Brazil.

2. Ten flocks in each house type were evaluated as follows: a) bird health: contact dermatitis on the breast and abdominal areas (CDE), bird soiling (BSO), footpad dermatitis (FPD), hock burn (HBU), lameness (LAM), fractures (FRA), bruising (BRU), scratches (SCR), dead on arrival (DOA), and diseases (DIS); b) house environmental measurements: relative humidity (RHU), temperature (TEM), air velocity (AVE), illuminance (ILL), ammonia concentration (NH₃), and carbon dioxide concentration (CO₂), and c) bird behaviour and affective states: bird behaviour (BBE), touch test (TTE), and qualitative behaviour assessment (QBA).

3. Statistical analyses were based on regression models for CDE, BSO, FPD, HBU, LAM and generalised linear models for DOA, FRA, BRU, SCR, and DIS. The Mann–Whitney test was used for RHU, TEM, AVE, ILL, NH₃, CO₂, and the t-test for TTE and LMO, with a specific regression model for BBE data and Principal Component Analysis for QBA.

4. According to odds ratio for worse scores for CS relative to OS, birds were less likely to have severe scores for CDE (P = 0.040 and P = 0.007), BSO (P = 0.031, P = 0.016, and P = 0.038), and HBU (P = 0.017), and had higher median values for AVE (2.3, 0.0–7.8 m s⁻¹ vs. 0.0, 0.0–4.3 m s⁻¹), lower NH₃ concentration (9.0, 0.0–64.0 ppm vs. 12.0, 0.0–60.0 ppm) and TTE scores (98, 96–100 vs. 67, 25–100). Worse results were observed in CS houses for higher stocking density (13.8 ± 0.2 birds/m² vs. 12.0 ± 0.2 birds/m²), RHU (74.5, 50.7–99.9% vs 72.3, 47.4–99.9%), and TEM (23.9, 14.6–29.2°C vs. 21.7, 12.9–30.1°C), lower ILL (16.0, 1.0–60.0 lx vs. 161.0, 8.0–2380.0 lx), less drinking (P = 0.007), more inactive behaviour (P < 0.001) and lower positive emotions, according to QBA (P = 0.028).

5. In the studied region and season, CS houses seemed to offer fewer welfare problems in terms of the health indicators; however, OS houses showed fewer behavioural restrictions and higher positive emotional states.

KEYWORDS:

• Aviary
• behaviour
• emotional state
• environment
• health
• poultry
• slaughter

Acknowledgments

The authors would like to thank all the professionals, farmers and a partner poultry meat industry, who contributed to this study. The anonymous reviewers greatly helped to improve the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the World Animal Protection. Also, this study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 001.