Comparison of egg production, quality and composition in three production systems for laying hens

Abstract

The increasing public concern for animal welfare has pushed the poultry sector to progressively replace conventional battery cages (CC) for laying hens with alternative systems such as enriched cages (EC) and aviaries (AV). The aim of this study was to compare laying performance, egg location, and egg quality associated with these three housing types. The experiment was conducted in twelve pilot-scale chambers fitted out with one of the three treatments. Each chamber housed 30 Lohmann LSL-Lite laying hens from 23 to 32 weeks of age. The available area was 492, 780, and 1120 cm²/hen for CC, EC, and AV, respectively. The EC and AV chambers were equipped with nest boxes, perches, and a pecking/scratching area (PSA). In the AV chambers, hens had free access to a space arranged in three levels with a wood shaving litter on the ground level as a PSA. Hen-day production was recorded and egg quality assessment included egg cleanliness, weight and proportion of each component (albumen, yolk, and shell) but also pH, Haugh unit, and meat spots for albumen; color intensity and blood spots for yolk; thickness and resistance for shell. The laying rate and egg weight were similar for CC and EC (around 96.5% and 59.5 g; P > 0.05). For AV, these parameters were significantly lower (77.2% and 58.6 g; P < 0.001) but the differences compared to the cage systems progressively reduced across time. Nearby 70% of the eggs were laid in the nests with EC while almost all of the eggs were laid on the litter at ground level with AV. The rate of clean eggs was around 77% for both cage systems compared to 14% for AV. Most of egg quality traits were identical for the three systems (P > 0.05) but there was a lower yolk proportion for eggs laid in AV (25.2% versus 25.7% for cages systems; P < 0.001) and higher shell resistance for eggs laid in CC (40.7 N versus 39.3 N for alternative systems; P < 0.001). Lower laying performance observed with AV could be explained by higher animal activity and competition for facilities, but these factors were not measured in this study. The reduction of the difference in egg productivity over time compared to cage systems suggest the need for a period of training/ adaptation for pullets/hens kept in such an environment. An enriched cage system seems a balanced solution that combines both laying productivity and improved animal welfare. Further research should be performed to improve acceptance and appropriate use of resources by birds in an aviary system.

Yield Performance, Laying Behaviour Traits and Egg Quality of Purebred and Hybrid Hens Reared under Outdoor Conditions

“…As known, in commercial strains the yolk weight increases with age [24,42] according to a higher food ingestion and lower request for body growth, but in our conditions in ER it did not change at 39 and 35 weeks of age, possibly due to an interaction between environmental conditions (high temperature), body growth, the laying activity and the hormonal status. Concerning the changes of eggshell incidence throughout the laying period according to the genotype, these may be due to interaction between environmental conditions and the physiological status of the birds: the hens laid eggs with different calcium depositions during each shell formation cycle or diluted the same calcium quantity over a larger surface [24,32] of the eggshell.…”

“…Causes affecting this behaviour during the first weeks of activity may be inexperience, while for the later periods this may be due to possible conditions of stress or disturbance among the birds [8,28]. The group size could be a factor affecting the rate of mislaid eggs by hens, as in presence of the same nesting area per hen a less competition for the nest in larger groups should occur, but the results are not conclusive as observed in hens reared in enriched cages and aviaries [24]. It is unknown whether the different genotypes had a different laying behaviour in relation to the artificial light schedule.…”

“…not conclusive as observed in hens reared in enriched cages and aviaries [24]. It is unknown whether the different genotypes had a different laying behaviour in relation to the artificial light schedule.…”

“…Relevant aspects to investigate on the egg production of purebred and hybrid genotypes under outdoor rearing conditions is the percentage of defective eggs from those suitable for retail, as stated above. For the intensively reared layer hybrid strains, the percentages of defective eggs throughout the laying period and their main causes are known [21][22][23][24]. Little is known about laying behaviour and damaged eggs of dual-purpose hybrids [17,25] and purebred hens reared under outdoor conditions [5].…”

“…These results are mainly due to the physiology of reproduction of the hens: at ovulation the rupture of the ovarian follicle at an area different from stigma and residues of the activity of the oviduct for the albumen synthesis can generate blood and meat spots in particular in genotypes with a genetic asset originally not addressed to a high laying activity [21,32]. (30,30,22,30); RM (25,16,21,24); HB (30,30,22,30); HW (30,30,22,30). (30,30,22,30); RM (25,16,21,24); HB (30,30,22,30); HW (30,30,22,30).…”