Sexual uniformity of males and females at mating-up will have long-term benefits for flock production and welfare. An immature male should never be mated up with a mature female and conversely mature males should not be mated with immature females. If sexual uniformity does not exist within the flock then mating-up should be delayed.

If males and females are not sexually uniform at mating-up:

• Flock fertility will be reduced, particularly for first hatches
• Floor eggs may be increased
• Female feathering may be poorer
• Overall flock welfare may be reduced
• Control over feeding may be poorer.

Mating-up should be started at around 21 weeks of age. Assess male and female maturity prior to mating up.