darkness. The light intensity was ca. 10 lux. The
room temperature was kept at 20–22°C.
The performance of the hens was recorded with
the daily number of hens and eggs, as well as the
feed intake per cage, box, and/or aviary. The health
of the hens was assessed daily.
Eggs for physical quality determination were
collected at 7 h at 28-day intervals for two consecutive
days following the procedure of Tumova
and Gous (2012) or Skrivan et al. (2013). All laid
eggs were examined. A total of 1509 eggs were
analyzed. The egg shape index (ESI; %) was determined
using the formula:
ESI = (egg width/egg length) × 100