Scanlan & Hargis (1989) had already suggested that
skin lesions in broilers are related to season.
On the other hand, when analyzing the evolution
of back scratches with age during the hot season, it
was observed that these lesions started to occur after
21 days. After 35 days, scratch rates sharply increased
to critical levels, higher than 10%, which may be
attributed to the increase in weight density per area
as compared to the starter period, when density was
probably no sufficient to cause scratch lesions. As birds
have more space to move around, they are less prone
to suffer scratches (Garcia et al., 2002; Fallavena,
2005). In the studies of Scanlan & Hargis (1989), a few
skin lesions were reported in three-week-old broilers.
Figure