Table 3.

The Effects of pre-hatch thermal manipulation on health and production performance in broilers

Thermal manipulation			Effects		References
Temperature, ºC	Time, h/d	ED	Increase	Decrease
15	30 min	18 and 19	Hatch weight, hatchability, body weight	Mortality, ascites (%)	[100, 175, 176]
	60 min	18 and 19	Breast muscle weight (% of BW)		[176]
30	12	10–18		Hatchability	[177]
33	3	15–17		Survivability (%), cerebellum (HSPB1,HSPB5,HSPB9)	[164]
34.6	4	16–18	Hatch time, hatchability		[178]
	24	16–18.5		Hatchability	[127]
36	3	0–5		Male chick body mass(g)	[132]
36.6	6	10–18	Hatchability, hatch time, body lipid content (%)	Serum T3 (ng/mL)	[100, 155, 179]
36.7	24	0–21	Embryo mortality	Hatchability	[76]
36.8	24	7–10 and 10–13	Carcass yield (%), grill loss (%)	Body weight	[92]
36.9	6	0–8	Wing length (mm), metatarsus length (mm)	Embryo weight (mm), Tibia length (mm)	[102]
		10–18	Embryo weight (mm), face length (mm), wing length (mm), metatarsus length (mm)		[102]
Standard incubation temperature (37.5–37.8 °C)
38.1	24	0–5	Plasma testosterone in males, breast muscle weight		[70]
38.2–38.4	2	18–21	Hatchability		[180]
	4	11–21	Female fat (%), meat redness	Male fat (%)	[181]
	24	18–21		Hatchability, body weight	[180]
38.3, 38.1 and 38.0	4	19, 20 and 21	Male sex ratio		[73]
38.3	24	0–21	Embryo mortality	Hatchability	[76]
38.4	4	18–20		Skin temperature after heat stress	[182]
38.5	3	16–18		IGF1, T3 and T4 concentration	[86, 105]
	18	12–18	Body, carcass, heart, liver weight, muscle (HSF2, HSF1)	Colon length, muscle (HSP108, HSP90)	[114, 162]
	12	12–18	Hatchability, ileum (HSP70, HSP90, HSPH1, GPX, and TXN), embryonic lipid metabolism, and thermotolerance	Hatch time, total VFA concentration	[71, 183]
	6	10–18	Triglycerides	Hatchability, embryo weight, glucose, liver, and heart weight	[140, 141, 184]
	6, 9 and 12	16, 17, and 18	Body weight		[25]
38.6	8	15–20	Male vocalizations, ANO2, TRAAK		[82, 185]
38.7	4	1–5	FCR		[186]
		8–12		Mortality	[186]
		14–18	FCR		[186]
	24	11–21		Salmonella counts in cecal contents	[187]
38.8	24	7–10 and 10–13	Body weight, carcass weight	Carcass yield (%),drip loss (%), grill loss (%)	[92]
38.9	24	7–21	Embryo mortality, hatchability, hatch weight, heart weight, body weight, total mortality, breast meat yield (%)		[96]
39	6	0–5		Female chick body weight	[132]
	9	12–18	PAX7, PCNA		[188]
	12	12–18	Body weight, IGF1		[188]
		13–21	Plasma T3 concentration		[90]
	18	12–18	Carcass, heart, liver, muscle (HSF2, HSF1), Body weight, myogenin, IGF1	Colon length, muscle (HSP108, HSP90), hatch weight, cloacal temperature	[114, 162, 188, 189]
		7–11	Hatchability, body weight, breast, thigh muscle, gut and liver weight, muscle (IGF1, GH), sarcomeres length		[118, 190]
		7–18	Lactate dehydrogenase (pectoral and thigh muscle)	Hatchability, body weight, thigh muscle weight	[118, 191]
		10–18	Body weight, SGLT1, GLUT2, FABP1, CD36, liver (NOX), Spleen (Catalase, NOX, SOD), body temperature, methylation of the IGF1 and GHR promoter regions	Hatchability, body weight, average daily feed intake, oxidative stress, serum T3, GHR, IGF1, IGF2 expression	[147, 189, 192, 193]
		11–15		Hatchability, body weight	[118]
		15–18		Hatchability, body weight, thigh muscle weight	[118]
	24	0–21		Body weight, feed intake, viability (%)	[194]
		13–21		Body weight (g), tibiotarsal rigidity, femoral breaking strength	[103]
39.1	16	10–20	Embryo mortality		[195]
39.5	3	8–10	Hatchability, mortality		[29]
		16–18	Mortality, Hatchability, corticosterone (ng/mL), HSP27, body weight, pectoralis muscle (% of BW), myofiber diameter (μm), PCNA, PAX7	Hatchability	[27, 29, 97, 110, 196]
		8–10 and 16–18	Hatchability, mortality		[29]
	6	16–18	Body weight, pectoralis muscle (% of BW), myofiber diameter (μm), PCNA, PAX7		[97]
	12	7–16	O2 saturation, mortality, myofiber diameter, feed intake, cold carcass weight (g)	CO2 partial pressure, feed intake (kg), FCR, female body weight (kg), hatchability, body weight gain, thyroxin, hatch time (h)	[21, 87, 99, 110, 197, 198]
	18	12–18	Breast muscle, liver, gizzard weight, muscle (HSF2)	Carcass weight	[114, 162]
	24	7–16	Plasma corticosterone concentration	Body weight	[20, 64]
39.6	6	0–8		Hatchability	[199]
		10–18		Hatchability
	8	15–20	Social retainment, ANO2, SCN5A	Hatchability	[82, 185]
40	3	6–8	Embryo mortality, T3, T4	Hatchability, red blood cell, white blood cell, packed cell volume	[68]
	6, 9 and 12	16, 17 and 18	Body weight, T4		[25]
	12	10–18		Hatchability	[177]
	18	12–18	Breast muscle, liver weight, muscle (HSF1, HSF2)	Carcass weight, muscle (HSP108, HSP90)	[114, 162]
40.5	3	15–17	Live sperm (%)	HSP70	[200]
40.6	4	16–18	Hatch time, plasma glucose (mg/dL), lactic acid (mmol/L)	Hatchability	[178]
	24	16–18.5		Hatchability, hatch weight, T3, T4	[127]
41	3	8–10	Metatarsus length (mm)	Embryo weight	[102]
		15–17	Cerebellum (HSPB9)	Hatchability, survivability (%), cerebellum (HSPB1)	[164]
		16–18	Embryo weight, metatarsus length (mm)	Wing length (mm), tibia length (mm)	[102]

Only significant (P < 0.05) post-hatch effects (excluding hatchability) are considered in the table