Effects of litter floor access and inclusion of experienced hens in aviary housing on floor eggs, litter condition, air quality, and hen welfare

Abstract

With different cage-free (CF) housing styles and management schemes, retailers have developed their own CF criteria. One highly debated aspect is if hens may be kept inside the system for part of the day—during the first few hours after lights-on. Research is lacking regarding the impacts of such a practice on hen welfare, incidence of eggs laid on the litter floor, litter condition, and air quality. This 14-mo field study was conducted to help assess such impacts. Hens (Dekalb White) in an aviary house (50,000-hen nominal capacity) were allowed to have full litter access (FLA) vs. part-time litter access (PLA) from 10:50 am to 9:00 pm, coupled with the absence or presence of experienced hens (1.5% of the population), hence a 2 × 2 factorial arrangement. The measured variables included a) incidence of floor eggs, b) percentage of birds remaining on litter floor at night, c) mortality, d) body weight (BW) and BW uniformity, e) litter condition (depth, moisture content, texture, amount removed, and bacteria concentration), f) environmental conditions, and g) welfare conditions (10 variables). Compared to FLA, PLA had a significantly lower incidence of floor eggs (1.4 ± 0.1 vs. 12.6 ± 1.1 eggs per hen housed as of 76 weeks of age (WOA), i.e., approximately 89% reduction), less manure deposition on the floor (0.53 ± 0.02 vs. 1.05 ± 0.04 kg/100 hens/d, dry basis, i.e., approximately 50% reduction), and lower ammonia concentrations due to drier litter (averaging 22% lower). Inclusion of 1.5% experienced hens in the young flock did not show benefit of reducing the incidence of floor eggs (P = 0.48). The percentage of hens remaining on the floor at night was low (< 0.01%) in all cases from 24 WOA onward. No differences were detected between FLA and PLA in hen welfare conditions, mortality, BW, BW uniformity, bacteria concentration in the litter, air temperature, or relative humidity.

Evaluation of nesting behavior of individual laying hens in an enriched colony housing by using RFID technology

“…The three distinct phases egg production in nest boxes indicate that the hens were exposed to a less competitive nest box during the third phase, which suggests that oviposition delay could be motivated by stress and its impact on hen's physiology [35] . It is important to understand the motivations of oviposition delay, especially considering that such delay may cause abnormal eggshell formation [35] , impair reproduction by the cessation of egg laying [49] , and trigger floor eggs in aviary or free-range housing systems [50] . It takes about 24 h after ovulation to complete the formation of an egg, which is divided into the following: 4 h for addition of the albumen layers to the yolk as it passes along the oviduct; 5 h for the membranes formation in the tubular isthmus and absorption of water and salts in the shell gland; and 15-16 h for the shell calcification [51,52] .…”

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

“…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].…”

Early training of hens: effects on the animal distribution in an aviary system

“…The capability of hens coming from a cage system to adapt into a cage-free system at transfer time is the first crucial step (Yang et al;2018, Janczak andRiber, 2015). It depends on several factors, such as genotype (Ali et al, 2016), age at the transfer time (MacLachlan et al, 2020), or access time to the floor litter (Oliveira et al, 2019). According to genetic producers, training layer hens to sleep at their arrival on the different levels of the system can improve space use and reduce subsequent egg laying on the ground (Hy-Line, 2016).…”