Significance of chick quality score in broiler production

Abstract

The quality of day old chicks is crucial for profitable broiler production, but a difficult trait to define. In research, both qualitative and quantitative measures are used with variable predictive value for subsequent performance. In hatchery practice, chick quality is judged on a binomial scale, as chicks are divided into first grade (Q1-saleable) and second grade (Q2) chicks right after hatch. Incidences and reasons for classifying chicks as Q2, and potential of these chicks for survival and post-hatch performance have hardly been investigated, but may provide information for flock performance. We conducted an experiment to investigate (1) the quality of a broiler flock and the relation with post-hatch flock performance based on a qualitative score (Pasgar&score) of Q1 chicks and based on the incidence of Q2 chicks and (2) the reasons for classifying chicks as Q2, and the potential of these chicks for survival and post-hatch growth. The performance was followed of Q1 and Q2 chicks obtained from two breeder flocks that hatched in two different hatching systems (a traditional hatcher or a combined hatching and brooding system, named Patio). Eggs were incubated until embryo day 18, when they were transferred to one of the two hatching systems. At embryo day 21/post-hatch day 0, all chicks from the hatcher (including Q2 chicks) were brought to Patio, where the hatchery manager marked the Q2 chicks from both flocks and hatching systems and registered apparent reasons for classifying these chicks as Q2. Chick quality was assessed of 100 Q1 chicks from each flock and hatching system. Weights of all chicks were determined at days 0, 7, 21 and 42. There were no correlations between mean Pasgar&score and post-hatch growth or mortality, and suboptimal navel quality was the only quality trait associated with lower post-hatch growth. Growth was clearly affected by breeder flock and hatching system, which could not be linked to mean Pasgar&score or incidence of Q2 chicks. Q2 chicks showed lower post-hatch growth compared to Q1 chicks but effects on flock performance at slaughter weight were limited because early mortality in Q2 chicks was high (62.50% at 7 days). We concluded that chick qualitative scores and the incidence of Q2 chicks may be informative for the quality of incubation, but are not predictive for post-hatch flock performance. Culling Q2 chicks after hatch is well-founded in terms of both animal welfare and profitability.

Effects of on-farm and traditional hatching on welfare, health, and performance of broiler chickens

“…Day-old chick quality, as measured by navel and hock scores ( Leksrisompong et al., 2007 ; van de Ven et al., 2012 ), was worse in OH compared with C chicks, confirming earlier results ( de Jong et al., 2019 ). This could be because of suboptimal hatching conditions at the farm or to a less strict removal of second grade chicks in the OH groups (practiced by the animal caretakers) as compared with the C groups that were selected at the hatchery.…”

Killing individual poultry on-farm—a survey among veterinarians and farmers

“… Van de Ven et al. (2012) stated that the early killing of low-quality chicks is necessary for moral reasons, but those chicks are also a risk for infections, a higher feed conversion ratio, and lower flock uniformity.…”

Effect of post-hatch transportation duration and parental age on broiler chicken quality, welfare, and productivity

“…Both Willemsen et al ( 2008 ) and van de Ven et al ( 2012 ) argued that the correlation between the Tona score and broiler performance is meaningful only when a considerable percentage of suboptimal quality (second-grade) chicks are included. In the current study, chick quality showed little variation overall (SD = 7; data not shown), which is most likely due to the post-hatch selection made by hatchery workers (similar to Willemsen et al, 2008 ).…”