Stocking Density Affects Stress and Anxious Behavior in the Laying Hen Chick During Rearing

Abstract

The recent increases in stocking density, in extreme cases resulting in ‘crowding’, have a major impact on poultry welfare. In contrast to available research on adult laying hens, there is a gap in the literature studying the rearing phase. The present study investigated the effects of stocking density during the rearing period on the welfare of the laying hen chick. The chicks were housed under one of three crowding conditions, increasing with age: undercrowding (500-1000-1429 cm2 per chick), conventional crowding (167-333-500 cm2 per chick), or overcrowding (56-111-167 cm2 per chick). The parameters evaluated encompassed behavioral and physiological factors related to anxiety and stress. We found that during the first 6 weeks, overcrowded chicks displayed more anxious behavior than undercrowded chicks, and both extreme densities induced higher corticosterone levels compared to chicks housed under conventional crowding. At 10 weeks of age, plasma corticosterone had dropped to the level of conventional crowding group in both groups, whereas feather corticosterone remained high only in the overcrowded group. We conclude that current conventional stocking densities do not seem to impair the welfare state of the laying hen chick, and that a three-fold increase or decrease of density influences corticosterone levels and anxious behavior, but within the adaptive capacity of the chick. Important side notes to this conclusion are that an increase of stocking density did result in a slower rate of adaptation, and that there could be long-term consequences of both the different stocking densities and/or increased costs of adaptation.

Corticosterone in feathers of laying hens: an assay validation for evidence-based assessment of animal welfare

“…(2017) . Every feather was thoroughly cleaned (based on Jenni-Eiermann et al., 2014 ; von Eugen et al., 2019 ) with distilled water and degreased by bathing it in HPLC-grade methanol (Carl Roth GmbH + Co. KG, Karlsruhe, Germany) for 2 to 4 s (based on Robertson et al., 2017 ). Based on the studies by Lattin et al.…”

“…In laying hens, the condition of the plumage and the integument acts as an indicator for feather pecking and cannibalism, both being behavioral disorders caused by various challenges the birds had or have to cope with ( Sepeur et al., 2015 ; Giersberg et al., 2017 ). Recent studies showed that the evaluation of animal welfare in birds may be carried out objectively and noninvasively with the measurement of the stress-related hormone corticosterone in feathers ( Bortolotti et al., 2008 ; Bortolotti et al., 2009 ; Fairhurst et al., 2011 ; Carbajal et al., 2014 ; Ganz et al., 2018 ; Johns et al., 2018 ; Weimer et al., 2018 ; Alba et al., 2019 ; von Eugen et al., 2019 ; Nordquist et al., 2020 ).…”

“…Subsequent studies on corticosterone in feathers were performed mostly in wild birds (e.g., Bortolotti et al., 2009 ; Koren et al., 2011 ; Lattin et al., 2011 ; Fairhurst et al., 2012 ; Lendvai et al., 2013 ; Harms et al., 2015 ; Kouwenberg et al., 2016 ; Aharon-Rotman et al., 2017 ; Freeman and Newman, 2018 ; Monclús et al., 2020 ), using feather corticosterone as a retrospective view on challenges the birds had to cope with during feather growth. Despite the wild birds, results of first investigations in poultry ( Berkvens, 2012 ; Carbajal et al., 2014 ; Jenni-Eiermann et al., 2015 ; Zeinstra et al., 2015 ; Johns et al., 2017 ; Weimer et al., 2018 ; Alba et al., 2019 ; von Eugen et al., 2019 ; Nordquist et al., 2020 ; Lindenwald and Rautenschlein, unpublished data) are also encouraging; however, in the absence of a standardized procedure, authors applied different methods to detect and quantify corticosterone in feathers. These variations, such as variations in the amount of feather material or methanol volume for the extraction, crushed vs. grind up feathers, and different methods for filtration or different assays, make it rather impossible to compare the results, properly ( Romero and Fairhurst, 2016 ).…”

Effects of Dark Brooder Rearing and Age on Hypothalamic Vasotocin and Feather Corticosterone Levels in Laying Hens

“…CORT Extraction from feathers was performed using a modified version of the protocol described in Bortolotti et al (30), as previously described in von Eugen et al (31) and Zeinstra et al (32). Extraction began by cleaning the feathers using aerosol solution of methanol.…”

Yerleşim Sıklığının Sprague Dawley Ratlarda Büyüme Performansı, Bazı Serum Oksidatif ve Nitrosatif Stres Parametreleri Üzerine Etkisi

“…Although there are different studies investigating the effects of the stocking density on various behavioral and physiological changes in rodents (Arakawa, 2005;Smith et al, 2005;Whitaker et al, 2007), domestic hens (Simsek et al, 2014;Eugen et al, 2019), quail (Ayasan et al, 2000;Toplu and Fidan, 2008;Bahsi et al, 2016), fishes (Jia et al, 2016;Rayhan et al, 2018), pigs (Cornale et al, 2015;Kim et al, 2016;Larsen et al, 2018), broiler (Qaid et al, 2016;Li et al, 2019) and primates (Yamagiwa, 1999;Duncan et al, 2013), no studies have investigated its effect on antioxidant capacity. In the present study, therefore, the effect of the stocking density on the antioxidant capacity in the rats was examined.…”