were collected the day of lay from hens
that were 61–70 weeks old. The eggs were inspected and candled, and
only eggs that were clean (no visible faecal, egg content or other dirt
on the shell) and intact (no hairline cracks, cracks or pinholes) were
used in the study. The eggs were stored under ambient conditions
(20–25 °C) for 1 to 2 days (shell contamination studies) or 2 to 3 days
(shell penetration studies) before use