Table 3. Comparison of egg quality in floor system and multi-tier system

Variable	Housing system
Variable	Floor	Multi-tier
Egg weight (g)
23 wk	53.98 ± 5.60^b	54.70 ± 3.87^c
30 wk	54.93 ± 6.00^b	58.11 ± 4.08^b
44 wk	64.99 ± 4.11^a	64.33 ± 4.59^a
Eggshell color
23 wk	29.18 ± 5.09	31.20 ± 2.98^a
30 wk	27.99 ± 3.95	28.92 ± 4.98^a
44 wk	27.48 ± 3.67	25.48 ± 3.67^b
Eggshell thickness (mm)
23 wk	0.34 ± 0.03	0.33 ± 0.03^b
30 wk	0.35 ± 0.02	0.34 ± 0.02^b
44 wk	0.37 ± 0.03	0.38 ± 0.03^a
Eggshell weight (g)
23 wk	6.94 ± 0.94^b	6.70 ± 0.83^c
30 wk	7.24 ± 0.66^b	7.56 ± 0.63^b
44 wk	9.15 ± 0.49^a	8.87 ± 0.90^a
Eggshell strength (kg/cm²)
23 wk	4.01 ± 0.89^b	3.51 ± 0.88^c
30 wk	4.82 ± 1.06^a	4.24 ± 0.99^b
44 wk	5.17 ± 0.78^a	5.03 ± 0.91^a
Yolk color
23 wk	7.26 ± 1.21^c	7.60 ± 0.86^b
30 wk	8.17 ± 0.90^b	7.79 ± 0.89^b
44 wk	10.75 ± 0.43^a	10.75 ± 0.62^a
Albumen height (mm)
23 wk	7.48 ± 1.66^ab	7.43 ± 1.28^b
30 wk	6.81 ± 1.55^Bb	7.87 ±1.37^Ab
44 wk	8.08 ± 0.87^a	8.24 ± 1.06^a
Haugh unit
23 wk	87.40 ± 9.80	87.21 ± 7.96^b
30 wk	83.19 ± 11.03	88.71 ± 8.71^b
44 wk	88.75 ± 5.03	89.52 ± 5.70^a

Mean ± standard deviation of several variables.
Means in rows with different superscripts differ significantly.
Means in columns with different superscripts differ significantly (p < 0.05).