Impact of different housing systems and age of layers on egg quality characteristics

The aim of this study was to investigate effects of conventional-cage (CC), enriched-cage (EC), and free-range (FR) systems and hen age on internal and external egg quality parameters of layers (Lohmann Brown). A total of 720 eggs were analyzed for egg weight (EW), shell weight (SW), yolk weight (YW), albumen weight (AW), shell thickness (ST), shell breaking strength (SBS), shape (SI), albumen (AI), yolk index (YI) of eggs, shell ratio of eggs (SR), albumen ratio of eggs (AR), yolk ratio of eggs (YR), yolk color (YC), and Haugh unit (HU). The highest EW, YW, AW, SW, AI, YI, HU (all P < 0.001), and SI values were found in FR system eggs compared with CC and EC system eggs (P = 0.045). The SBS, ST, YC, SR, YR, and AR were found similar in all housing systems. There was an interaction between the housing system and hen age for EW, SW, YW, AW, SBS, ST, AI, YC, HU, AR (all P < 0.001), SI (P = 0.003), SR (P = 0.001), and YR (P = 0.001) of eggs. It can be concluded that eggs in the FR system were better in overall quality than eggs from CC and EC systems.