Yes, the arrival of male chicks in layer production is primarily due to sexing errors during the sorting process at hatcheries. Sexing errors are more common in breeds where distinguishing males from females is difficult, such as some auto-sexing breeds or when sexing by vent inspection.
Regarding egg size reduction in layer flocks with sexing errors, this happens because male chickens do not lay eggs, but their presence can lead to competition for feed, space and resources, which may stress the hens and affect egg production and size.
In broiler production, reducing bird size due to sexing errors is not a concern the same way it is in layers because:
1. Broilers are raised for meat and not egg, so sexing errors do not impact egg size.
2. Most commercial broilers are grown as mixed-gender because both males and females are used for meat.
3. Males naturally grow faster than females, so in a mixed flock, the males may be bigger, but this is not a disadvantage.