Critical Assessment of Chick Quality Measurements as an Indicator of Posthatch Performance

Abstract

For hatcheries, not only is it important to have a high level of hatchability, but the quality of the chicks provided also has to be good, because broiler farmers are looking for chicks with a high growth potential, resulting in a greater slaughter yield at the end of the rearing period. However, chick quality has proven to be a difficult and subjective matter to define. Therefore, the aim of this study was to investigate the predictive value of different chick quality measurements for BW at slaughter age. Body weight, chick length, shank length, and toe length measurements as well as Tona score determination were performed on 1-d-old chicks and were linked to posthatch performance parameters. Different breeder lines (Cobb and Ross) and breeder ages (39, 42, and 53 wk of age) were used to investigate line and age effects. In addition, variability between people and repeatability in time of these quality measurements were determined. Body weight at 7 d of age appeared to be the best predictor of BW at slaughter age among all the quality measurements performed. Body weight at 1 d of age had the second greatest predictive value, closely followed by the ratio between BW at 1 d of age and chick length squared. Chick length and shank length both had low to no predictive value whatsoever for posthatch performance. The lack of significant correlations between the Tona score and posthatch performance could be explained by the absence of day-old chicks with anomalies (and thus a suboptimal Tona score) because a distinction had already been made, as is done in practice, between top-grade and lower grade chicks.

Thermal stimulation of Ross®-lineage embryos on a commercial scale

“…Organs involved in thermoregulation (hypothalamus, thyroid, and pituitary gland) develop during growth phase, but their final maturation occurs in the last days of incubation and shortly after hatching (FLORES et al, 2013 Different temperatures during incubation may have different effects on broiler weight after hatching, and may affect the final slaughter weight (TONA et al, 2004;WILLEMSEN et al, 2008); these variations may also increase tolerance to environmental temperature challenges (MORAES et al, 2003;COLLIN et al, 2007), alter post-natal growth (COLLIN et al, 2005;HALEVY et al, 2006), and resulted in improved performance on site at 38 days of age (SHINDER et al, 2009). These long-term adaptations occur after application of periodic thermal manipulation during the last phase of maturation, when embryos are most responsive to "training" (TZSCHENTKE & HALLE, 2009).…”

Delay in feed access and spread of hatch: importance of early nutrition

“…Nowadays, the first 7 d represent approximately 17% of the growing period in time and 5 -10% in weight as a percentage of final body weight (Lilburn, 1998;Havenstein et al, 2003). Moreover, the body weight at 7 d of age appears to be a good predictor for the body weight at slaughter age, with correlations ranging from 0.4 to 0.5, depending on breeder line and parent stock age (Willemsen et al, 2008).…”

“…In addition, the added 'hatch window' of 24 to 48 h (early versus late hatchers) must be taken into consideration (Decuypere et al, 2001) (Figure 1). Due to this spread in hatch, chicks not only differ in biological age, but also in quality (Bamelis et al, 2005;Tona et al, 2003;Willemsen et al, 2008). Figure 1 Schematic overview of the difference between biological and chronological age as the interaction with time of hatch within a hatching window is highlighted.…”

Quality assessment chicks from different hatcher temperatures with different scoring methods and prediction of broiler growth performance

“…Incubation factors such as temperature, humidity, turning and ventilation influence day-old chick quality in the way of chick weight, body length, activity, yolk sac uptake, navel closure on hatching day and post-hatch growth performance (Meijerhof 2003;Willemsen et al 2008). Poor incubation conditions can cause insufficient embryo development and lower hatchability (Meijerhof 2003).…”

“…Poor incubation conditions can cause insufficient embryo development and lower hatchability (Meijerhof 2003). Incubation temperature is one of the most important factors to assure optimum chick quality and also for post-hatch broiler performance (Lourens 2003, Willemsen et al 2008, Ipek et al 2014. Embryos with high growing rates are sensitive to temperature fluctuations, and small deviations from optimum ranges have negative effects on hatchability and hatchling quality (Molenaar et al 2010).…”