To support the development of broiler breeders and get them ready for egg production, often the grower feed in rearing is changed for a pre-breeder feed at 16 to 18 weeks of age. Typically, a pre-breeder feed is more or less simliar to a feed that is used in production, except for the level of Calcium.
However, we have to question if we want the males to receive this pre-breeder feed as well. Pre-breeder feed is higher in energy and protein to develop the females for egg production, but often the males are developed earlier than females and can even be over-developed compared to the females, which can create problems with overweight and agressiveness.
Also when a special male feed is used in production (usually lower in calcium, protein and energy than a feed for females) we have to realize that feeding a pre-breeder layer feed for males in the last part of rearing can cause problems, as the bird is then switching from a feed high in protein and energy at the end of rearing back to a feed low in protein and energy.
If in production the males are receiving the same feed as females, perhaps its better to keep the males on the grower feed until the end of the rearing period. If the males are getting a separate male feed in production it might be better to switch from the grower feed directly to that male feed, and skip the pre-breeder for the males in the last period of production.
One can even consider to keep the males on a grower feed during production, as a grower feed and a male feed are normally quite similar, which reduces the need for a separate small quantity of male feed. However, this need to be discussed with a nutritionist to see how much similarity there is between the grower and the male feed, and to see if the different pre-mix and perhaps the presence of a coccidiostat in the grower can cause problems.