Spiking (partly replacing the males in a breeder flock halfway during the production period) is often done to maintain fertility. By introducing young males, we hope to increase the general condition of the flock with a positive effect on  hatchability. Downside of the system is that a small group of young males need to be available, and a bio-security risk is introduced

Part of the positive effect of spikng is related to the breaking of the ranking in hierarchy in the group of males. This effect can be achieved by intra spiking as well. 

Intra spiking is the system of taking the males from different houses, mixing them and bringing them back in the flock. In this way the ranking of males in the system is disrupted, and less dominant males have the opportunity to become more dominant.