Based on the results of work at the Federal University of Paraná, the grouping of chicks by weight does not produce more uniform broilers at the end of the production period.

In a paper in Journal of Applied Poultry Research, Roberto Montanhini Neto and colleagues report that they evaluated the effect of the grouping of day-old chicks according to initial bodyweight on the subsequent homogeneity and distribution of the weight of the broilers at harvest.

Two treatments (placement methods) were tested: in one treatment (random), the chicks’ placement was random and not grouped by initial weight; in the other treatment (homogeneous groups), the chicks were grouped according to their initial weight.

The broilers were individually weighed upon placement and again at 21 and 42 days of age.

The lowest dispersion of the weight at placement was observed for the homogeneous groups but the dispersion did not differ between the treatments at the subsequent weighings.

Despite the difference in placement, Neto and co-authors concluded that the distribution of the weight data for the two groups did not differ between 21 or 42 days of age.

Reference

^{Neto R.M., D. Surek, C. da Rocha, F. Dahlke and A. Maiorka. 2013. The effect of grouping one-day-old chicks by body weight on the uniformity of broilers. J. Appl. Poult. Res. 22(2):245-250. doi: 10.3382/japr.2012-00636}