Wrinkled eggshells signal chicken stress, experts explain

A rural producer in Vacaria, Rio Grande do Sul, Brazil, recently discovered an egg with a wrinkled shell, prompting questions about its cause. According to zootechnician Marconi Ítalo from São Paulo State University (Unesp), such shell deformities are typically linked to stress experienced by the hen during the eggshell formation process. The entire egg production cycle takes about 25 hours, with the final 18 hours spent in the uterus where the calcium shell is formed. Stressful conditions, such as loud noises like heavy rain on metal roofs, can cause the hen's uterus to contract, resulting in a wrinkled shell that reflects these contractions. Other contributing factors to stress and shell deformation include high temperatures exceeding 25°C, deficiencies in calcium and phosphorus in the hen's diet, overcrowding, and the hen's advanced age or health issues. If deformed eggs become a frequent occurrence, consulting a veterinarian is recommended to assess the flock's health and identify the underlying cause. Wrinkled eggs are safe for consumption as long as the shell is intact and free from cracks, and the egg has been stored properly; the issue is primarily aesthetic and does not typically affect the egg's internal quality. To mitigate stress in hens, simple environmental adjustments can be made, such as hanging old CDs to stimulate interaction, installing perches to enhance security, or providing fruit nets filled with hay or dry grass for pecking, which helps reduce stress and boredom.