Cold stimulations during egg incubation were reported to limit the occurrence of ascites in broilers subjected to cold temperature after 14 d of age. However, data are lacking on the impacts of such strategy in case of cold temperature conditions at start. This study aimed to evaluate the effects of incubation and posthatch cold challenge on performance, breast muscle integrity, and meat processing quality in broiler chickens. Ross 308 eggs were incubated under control temperature (I0, 37.6°C) or subjected to 15°C during 30 min on day 18 and 19 of incubation (I1). Chicks from each group were reared in floor pens either at standard rearing temperature (T0), from 32°C at 0 d to 21°C at 21 d of age, or exposed to colder rearing temperature (T1), from 29°C at 0 to 21°C at 21 d of age. All birds were then kept at 21°C until slaughter (day 40), when body weights (BW), feed conversion ratio (FCR), breast muscle yield, meat processing quality, and the occurrences of meat defects, hock burns, and pododermatitis were recorded. No significant impact of incubation conditions on hatchability was observed. At day 40, BW was more under T1 than under T0 conditions, with T0 females (but not males) presenting more BW after I1 than after I0 conditions. In the whole period, T1 chickens presented lower FCR than T0 chickens and higher breast meat yields at day 40. The occurrence of white striping was more in I1T1 males than in all other groups, except for the I0T1 males. Hock burns were more frequent in I1T1 males than in all females and I0T0 males, whereas the occurrence of pododermatitis was lower in T0 males than in other groups. Despite some positive effects of I1 incubation on growth after starting under low ambient temperature, this study reveals the limits of such strategy concerning chicken health and welfare, demonstrating that early thermal environment is a major component of the quality and sustainability of chicken meat production.

中文翻译：

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孵化过程中短暂的冷暴露和产后的低温会影响肉鸡的性能，胸肉质量和福利参数。

据报道，卵孵化过程中的冷刺激可以限制在14 d龄以后经受低温的肉鸡中腹水的发生。但是，在开始时温度较低的情况下，缺乏有关这种策略影响的数据。这项研究旨在评估孵化和孵化后冷挑战对肉鸡生产性能，胸肌完整性和肉加工质量的影响。将罗斯308卵在控制温度（I0，37.6°C）下孵育，或在孵育的第18天和第19天（I1）在30分钟内置于15°C下。将每组小鸡在标准圈养温度（T0）下从0 d的32°C升高到21 d龄下的21°C或以较低的饲养温度（T1）从29°C的温度饲养在地板圈中在21 d时为0至21°C。然后将所有鸡只保持在21°C下直到屠宰（第40天），记录体重（BW），饲料转化率（FCR），胸肌产量，肉加工质量以及肉缺陷，飞节灼伤和足底皮炎的发生。没有观察到孵化条件对孵化率的显着影响。在第40天，在T1下的体重比在T0条件下更多，在I1之后，T0雌性（而非雄性）的BW比I0条件下更多。在整个时期，第40天，T1鸡的FCR低于T0鸡，胸肉产量更高。除I0T1雄性外，I1T1雄性的白色条纹发生率高于所有其他组。在I1T1男性中，比在所有女性和I0T0男性中，飞节烧伤更为频繁，而在T0男性中，足底皮炎的发生率比其他组要低。