Influence of floor egg shell cleanliness and cleaning treatment on hatchability and chick quality

A total of 3,600 floor eggs from a 59-week-old Cobb 500 parent flock were collected to examine the effects of shell cleanliness and cleaning treatment on incubation results. The eggs were divided into two equal groups according to the cleanliness of the shell: eggs with a visually clean shell (clean eggs) and eggs with a dirty shell (dirty eggs). Depending on the cleaning treatment, clean and dirty eggs were divided into three equal groups: eggs that were not cleaned at all (intact), eggs that were cleaned with metal wire (scraped eggs) and eggs that were washed (washed eggs). Cleaning treatment significantly affected egg weight loss (p = 0.057). The hatchability of set eggs was under significant influence of egg cleanliness (p = 0.018), while the hatchability of fertile eggs was under significant influence of egg cleanliness (p = 0.003) and cleaning treatment (p = 0.029). Significant influence of shell cleanliness (p = 0.000) and cleaning treatment (p = 0.000) on egg contamination was also observed. Early, middle and total embryonic mortality were not significantly influenced by shell cleanliness and cleaning treatment, in contrast to late mortality which was under significant influence of egg cleanliness (p = 0.028). The number of first grade chicks per incubator tray was significantly influenced by egg cleanliness (p = 0.018). Chick weight and length were not significantly affected by shell cleanliness and cleaning treatment. The study showed that washed eggs had a higher weight loss compared to intact and scraped eggs. Dirty eggs had a lower hatchability, a higher percentage of contamination and late mortality as well as a lower number of first grade chicks per incubation tray, compared to clean eggs. Cleaning treatments did not have a significantly positive effect on the incubation results of either clean or dirty eggs. Washing treatment had a particularly negative effect on dirty eggs as they had reduced hatchability and increased contamination. The absence of a positive effect of scraping and washing treatment on the incubation results makes justification of these cleaning treatments for floor eggs doubtful.