Table 1. Average phenotypes and testing for differences between selection lines for high and low maternal egg investment.

Trait	High	Low	t	df	P
Egg size
Egg size (g)	12.46±0.94	11.12±0.91	6.49	78	<0.001
Dry mass (g)	3.857±0.334	3.411±0.325	6.04	78	<0.001
Egg components
Wet albumen (g)	7.851±0.570	6.879±0.523	7.95	78	<0.001
Dry albumen (g)	0.912±0.088	0.789±0.070	6.96	78	<0.001
Wet yolk (g)	3.620±0.413	3.228±0.365	4.49	78	<0.001
Dry yolk (g)	1.899±0.229	1.699±0.213	4.05	78	<0.001
Dry shell (g)	1.044±0.090	0.922±0.077	6.51	78	<0.001
Yolk/albumen ratio	0.461±0.042	0.469±0.036	0.87	78	0.387
Fecundity
Laying rate	0.915±0.034	0.922±0.044	0.71	78	0.478
Laying interval (hours)	24.18±0.55	24.07±0.55	0.88	77	0.383
Body Size
Tarsus length (mm)	40.6±1.2	39.3±1.4	4.55	78	<0.001
Body mass (g)	281±24	260±28	3.57	78	<0.001

Mean±s.d. of traits measured in generation 4 are presented. Data from the two replicates were pooled. Significant differences are displayed in bold.