RESULTS
Technical and Economic Variables
Body weight at slaughter increased (P < 0.001) progressively
with age, 63-d-old broilers being 2.5-fold
heavier than 35-d-old birds (Table 1). For the fi nishing
period, from 21 d to slaughter, individual ADFI was 1.4-
fold greater for 63-d-old than for 35-d-old broilers. The
ADG and G:F for the same period increased 1.2 and decreased
1.1-fold, respectively (P < 0.001). Bird mortality
increased (P < 0.01) from 49 d of age, reaching 5- to
7-fold greater values for broilers reared until 63 d than
for broilers reared until 35 or 42 d.
The economic consequences were estimated with
regard to broiler age at slaughter by taking into account
broiler performance. Although the total weight of chickens
produced, and therefore the profi tability per square
meter, greatly increased, the ratio between profi tability
and feed cost gradually decreased with age (Table 1).
The net gain, which takes into account both the feed and
rearing costs, reached a maximum between 42 and 49 d
of age, and then decreased between 56 and 63 d of age.