Eggs were collected from commercial caged layer flocks in early, mid, late and very late lay. Eggs were candled and scored for translucency. Cuticle cover was estimated using MST cuticle stain and a Konica Minolta hand-held spectrophotometer. Traditional measures of egg quality were determined using specialised equipment (TSS, U.K.) Shell ultrastructural features were scored following plasma ashing of shell samples and viewing under a benchtop scanning electron microscope. Translucency tended to be higher in late lay flocks and shell quality was lower. Cuticle cover was relatively uniform for young flocks but much more variable in older flocks. The incidence of unfavourable shell ultrastructural features was higher for older flocks. This study is on-going so, as the sample size increases, new insights will be obtained.