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.

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Cilj rada bio je da se ispitaju vrijednosti parametara inkubacije(gubitak mase, oplođenost, valivost uloženih i oplođenih jaja, te ukupan, rani,srednji i kasni embrionalni mortalitet) rasplodnih jaja različite mase teškog linijskoghibrida Cobb 500. Ukupno je ispitano 600 jaja podijeljenih u četiri jednake grupe(n=150) prema njihovoj masi: 57,5 – 62,5 (S); 62,6 – 67,5 (M); 67,6 – 72,5 (L) i 72,6 –77,50 g (XL), a vrijednosti parametara inkubacije određene su i statistički obrađenestandardnim metodama. Masa jaja uticala je statistički značajno na gubitak masejaja tokom inkubacije (p<0,05), pri čemu je taj gubitak bio veći kod jaja manje (grupaS 11,10% i grupa M 11,40%) u odnosu na jaja veće mase (grupa L 10,42% i grupaXL 10,31%). Valivost uloženih jaja u grupama S, M, L i XL iznosila je 76,0; 75,3;78,7 i 66,0%, redom, a oplođenih 82,0; 81,3; 82,5 i 71,7%, redom, pri čemu nijeustanovljena statistički značajna razlika (p>0,05). Masa jaja nije statistički značajnouticala na razliku u vrijednostima mortaliteta embriona, iako je kod jaja grupe XLustanovljena viša vrijednost ukupnog, ranog i kasnog mortaliteta u odnosu na ostalegrupe jaja. Rezultati ovog istraživanja ukazuju na niže vrijednosti valivosti i višimortalitet embriona u inkubaciji jaja izrazito velike mase u odnosu na ostale grupe,zbog čega izboru jaja za nasad treba posvetiti posebnu pažnju i u pogledu mase.

The aim of this study is to determine whether the site of oviposition has an impact on the results of incubation of broiler hatching eggs. In order to determine this, eggs laid in the nest, eggs laid in the nest and then placed on the floor to cool and eggs laid on the floor were compared. All eggs had a visually clean shell, including eggs laid on the floor. A total of 1,800 eggs from a 59-week-old Cobb 500 parent flock were examined, divided into three groups (n = 600) with 4 replicates (150 eggs per replicate). Compared to nest eggs, floor eggs had significantly higher weight loss (p0.05), lower hatchability of set eggs and total embryonic mortality (p0.01), as well as a lower number of first grade chicks per incubator tray (p0.05). The percentage of contamination differed significantly between groups and it was the highest in floor eggs and the lowest in nest eggs (p0.01). Nest eggs placed on the floor did not differ statistically significantly from nest and floor eggs in hatchability, total mortality and number of first grade chicks per incubator tray, although these eggs achieved more favourable results compared to floor eggs (p0.05). The applied treatments did not affect the weight and length of the chicks (p0.05). This research confirmed that floor eggs, despite their clean shell, have lower hatchability and a higher percentage of contamination than nest eggs, which emphasizes the importance of maintaining hygiene in nests and preventing the appearance of floor eggs in order to ensure the maximum number of eggs suitable for incubation.

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