Animal welfare of embryos and newly hatched chicks: A review

The welfare of farm animals is a hotly debated issue today. There are few technical materials available focused on hatcheries that address and incorporate practices adopting the welfare level required by civil society. However, about 33% of the production period of a broiler chicken occurs on the hatchery. Recent studies have shown that day-old chick production has points that need to be improved. Technical standards indicate that the process of welfare should begin during egg storage such that the best conditions are provided for embryos prior to incubation. Storage until 28 days at temperatures above 12ºC can kill embryos, while exposure of eggs to 30 ºC until 14 days causes a negative impact under the hatchability. The available results regarding in ovo nutrition show that it should be considered for benefit neonate quality since inoculation of substances such vitamin E (60.4 IU) promote better incubation results. Feeding immediately after hatching is a management for welfare because animals feed-fed soon after hatch perform better up to 35 d. The most criticized point in hatcheries is the slaughter of neonates, for which some strategies are being investigated, including the use of dual-purpose aptitude strains, in ovo sexing by different methodologies, sex inversion and hormonal-based sexing. It is noted that procedures involving bird incubation require greater attention to welfare. Therefore, it is necessary to align theoretical knowledge with practical applications so that the demands of society, as well as those of industry, are met.