**Author details**

*Advances in Poultry Nutrition Research*

transmission of infectious diseases.

marker for this purpose.

**Acknowledgements**

sincere thanks.

**Conflict of interest**

of DT2 CNPq process number 314636/2018-8.

There is a projection of a 46.4% increase in chicken meat production by 2023 Simultaneously, there is a growing demand for information on ethical aspects of animal production. In a study conducted between the states of Paraná, Santa Catarina and Rio Grande do Sul, evaluating the condemnation of birds, it was observed that injuries were the main cause of condemnation in 2015, followed by dermatoses. These same authors report that the third highest incidence of condensation is associated with dorsal skull myopathy [49]. In the State of Paraná, which slaughter more than the others in absolute numbers, the percentage of convictions increases. The progressive increase in rates of injury conviction, inadequate bleeding, arthritis and aerosaculitis can indicate important aspects of well-being.

The increase in convictions caused by arthritis may indicate that the industry has undergone significant changes in recent years, which result in a negative impact on the welfare of birds [51]. This information goes from other information obtained with the weight gain of these animals since birds are gaining weight very quickly. These same authors indicate that genetics may be the main cause of skeletal disorders in fast-growing breeds, causing a lack of activity in the birds, which because they are very heavy, aggravates the problem [52, 53]. The high stocking density is also related to the reduction of air quality, increased thermal stress and increased

A study by [30] observed that for birds with WB there were changes in the birds' behavior since they associated this difference with the change in the way of walking of these animals. Which may suggest possible effects associated with loss in the welfare of these birds. Another study by [16] have already reported a possible change in

Approach to the welfare of these birds is essential, as it compromises the structure of the carcass as a whole and can directly compromise its mobility. In reference [29] it was observed a degree of structural abnormality in all samples of chickens with rapid weight gain. However, in another study by [16] reported that there are symptoms in birds that did not affect all individuals affected by WB, however, there may be possible links with the environment. However, there is still no quantitative information on whether WS or WB affects the behavior, ability to walk or the welfare of these birds. There is a chance that these myopathies would harm mobility and, therefore, have welfare implications for animals. With this information, it would be interesting to study a variable that can correlate the stress level of birds with the myopathies associated with this proposal, with cortisol being an excellent

The authors are tankful the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), and Conselho Nacional de Pesquisa (CNPq) for the possibility of developing this study. Especially the author MRP thanks for the granting

The authors are especially grateful to Dr. Elza I. Ida for the assistance during the execution of this review, with suggestions and valuable professional experience in research advice. She is a great researcher on the Brazilian scene. To her, our most

The authors declare that there is not any conflict of interest.

the growth conditions of these birds, directly affecting their welfare.

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Mayka Reghiany Pedrão1 \*, Rafaele Martins de Souza1 , Helder Louvandini2 , Patricia Louvandini2 , Roberta Barreiro de Souza1 , Natália de Morais Leite1 and Fábio Augusto Garcia Coró1

1 Technological Federal University of Paraná (UTFPR), PPGTAL, Londrina, Brazil

2 Animal Nutrition Laboratory, Nuclear Energy in Agriculture Center of the University of São Paulo (CENA), University of São Paulo (USP), Brazil

\*Address all correspondence to: maykapedrao@utfpr.edu.br

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
