Feed Strategy - June 2018 - 17
FeedStrategy ❙ 17
male is crossed with a standard white male broiler.
In this case, the growth rates and carcass conformation are intermediate.
As standard commercial breeds have gotten heavier, the breast meat yield has increased (approximately
30 percent) - fitting with the demand for white meat.
Older style breeds have a very different carcass confirmation, with 10 percent less breast meat but larger legs
Growth rates of different broiler breeds
Average daily gain per week (g)
Fast x slow
Broiler performance objectives
In standard commercial broiler production, birds are grown for about 39
days, dependent on their destined end
product. However, slower-growing
birds are kept for significantly longer:
■ Indoor: More than 49 days
■ Free range: More than 56 days
■ Organic: More than 70 days
The exact production period
will be dependent on any accreditation
scheme producers are part of, as well as the
market into which they will be sold.
In several of the breed manuals, different growth
rates are quoted: first, that of the bird's true genetic
potential and, second, for the daily gain prescribed by
certain certified programs.
Along with management guidelines, minimum
age of slaughter and maximum daily growth rates are
required for accreditation. For example, GAP suggests
a growth rate of less than 50 grams a day, significantly
In week 6, there is more than a 50 percent
difference in the growth rates of fast- and slowgrowing broiler breeds.
lower (23 percent) than the industry average of 61
grams per day. Comparison of the (as hatched) growth
rates of three commercial breeds - fast, fast-slow
cross and a pure slow-growing breed - shows that
there may be a greater difference between male and
female slower-growing breeds, leading to recommendations for some to be reared separately and fed a differently specified diet.
Slow-growing broiler nutrition
Industry-recommended feed formulas for a fastand slow-growing broiler breed vary; however, as they
eat less feed each day, overall intake will be lower.
Based on research and expert thinking, the following
list provides some points to consider:
Meat yields of fast- and slow-growing broiler breeds
Chilled eviscerated carcass yield
or WOG (% of liveweight)
Boneless breast with skin (% of WOG)
Whole leg (% of WOG)
Wing (% of WOG)
a, b, c Means within the same row without common letters are different (P<0.05)
Source: Tatijana Fisher, University of Kentucky
Compared with modern commercial breeds, slower-growing breeds have lower carcass and breast meat yields.
June 2018 ❙ www.WATTAgNet.com