TABLE 2.

Lower than optimum incubation temperature: Effects on the embryo’s physiology and post-hatch growth.

References	Strain	Temperature treatment during incubation (Day/temperature)	Differences in compared to control (37.5–37.8°C) incubation
			Incubation duration	Hatchability	Yolk sac/yolk free chick W a /Chick W/chick length	Morphological and physiological effects	Post-hatch growth performance
Lourens et al. (2005)	ND b	D1-7/36.7°C (EST) c	ND	=	=/↓/ND/↓	ND	ND
Joseph et al. (2006)	Ross 308	D 0–10/36.6°C (EST)	ND	↓	↑/=/↑/↓	ND	↓ BW e at 21 and = FCR, CW ↑Abdominal fat
Willemsen et al. (2010)	Cobb 500	D 16–18.5/34.6°C (IT) d	↑	↑	↓/ND/ = /ND	↓ Blood T3 and triglycerides	ND
Janisch et al. (2015)	Cobb 500	D 7–10 or 10–13/36.8°C (IT)	ND	ND	ND/ND/ND/ND	ND	= BW, CW, DL
Maatjens, et al. (2016)	Ross 308	ED15-21/35.6°C (EST)	↑	=	=/↑/ND/ND	↑ Liver W = Spleen and intestine W ↓Stomach W	ND
		ED15-21/36.7°C (EST)	↑	=	=/↑/ND/ND	↑ Liver W =Spleen, stomach and intestine W	ND
Almeida et al. (2016)	Cobb 500	D13-21/36°C (IT)	↑	=	=/=/ND/ND	↑Blood cholesterol ↓Adipocytes size	ND
Hamidu et al. (2018)	Ross 708	D15-21/36°C (IT)	↑	ND	=/=/=/=	↓ O2 consumption at E16 and 17	ND
		D15-21/36.5°C (IT)	=	ND	= / = / = / =	↓ O2 consumption at E16 and 17	ND
	Ross 308	D15-21/36°C (IT)	=	ND	=/=/=/=	=O2 consumption E15–21	ND
		D15-21/36.5°C (IT)	=	ND	=/=/=/=	=O2 consumption E15–21	ND
Morita et al. (2016)	Cobb 500	D 13–21/36°C (IT)	↑	ND	=/=/=/ND	↓ Blood vessel number, T3 and growth hormone	ND
Wijnen et al., (2020)	Ross 308	D15-21/36.7°C (EST)	↑	ND	=/=/=/↓	↑ Blood glucose, heart and stomach W	= FCR at 40 d

^aW: weight.

^bND: not determined.

^cEST: eggshell temperature.

^dIT: incubation temperature.

^eBW: body weight.

^fFCR: feed conversion ratio.

^gCW: carcass weight.

^hBrst: breast.

ⁱDL: drip loss.