. 2020 Aug 19;7:533. doi: 10.3389/fvets.2020.00533

Table 5.

Effect of the test period on egg physical characteristics.

Test period (age of hens¹)	1st (wk 28)	2nd (wk 40)	3rd (wk 52)	4th (wk 64)	5th (wk 76)
Egg weight (g)	63.15^d ± 0.37	66.35^a ± 0.52	67.64^ab ± 0.52	69.11^bc ± 0.52	69.91^c± 0.53
Egg width (mm)	44.12^a ± 0.09	44.56^ab ± 0.13	44.75^bc ± 0.13	44.63^b ± 0.13	45.17^c ± 0.13
Egg height (mm)	57.59^b ± 0.16	58.89^b ± 0.22	60.03^b ± 0.22	61.17^a ± 0.22	61.46^a ± 0.22
Shell color (%)	34.86^b ± 0.42	39.65^a ± 0.60	38.91^a ± 0.60	37.50^ac ± 0.60	36.18^bc ± 0.60
Shell strength (N)	43.75^a ± 0.63	41.18^ab ± 0.88	38.59^bc ± 0.88	36.66^c ± 0.88	32.77^d ± 0.89
Yolk diameter (mm)	39.46^c ± 0.13	43.32^ab ± 0.18	43.78^a ± 0.18	43.71^a ± 0.18	42.64^b ± 0.18
Albumen pH	8.47^b ± 0.01	8.39^ab ± 0.02	8.41^ab ± 0.02	8.32^a ± 0.02	8.46^b ± 0.02
Yolk pH	6.19^c ± 0.01	6.13^a ± 0.01	6.07^ab ± 0.01	6.03^b ± 0.01	6.30^c ± 0.01
Yolk color (Roche)	11.08^a ± 0.04	11.04^a ± 0.05	11.08^ab ± 0.05	11.29^b ± 0.06	11.10^ab ± 0.06
Albumen height (mm)	7.53^c ± 0.10	6.35^a ± 0.14	6.33^a ± 0.14	5.64^b ± 0.14	5.39^b ± 0.14
Haugh units	85.17^c ± 0.81	75.27^a ± 1.15	75.29^a ± 1.16	68.50^b ± 1.14	66.94^b ± 1.16

Values are expressed as least squares means (LSM) ± SEM.

^{a, b, c, d}

different superscripts on LSM values within a row indicate a difference (P < 0.05).

Age of the hens in weeks (wk) at the time of egg sampling.