A selection experiment on a white leghorn strain under Ahemeral light‐dark Cycles

Selection was carried out for increased ovulation frequency in two flocks; under ahemeral (9 generations of selection) or normal (8 generations) light‐dark cycles. 2. By the use of an ahemeral regime, the barrier to progress imposed by the limit of one ovulation in each light‐dark cycle was evaded. 3. Both flocks achieved a considerable increase in oviposition frequency but so far there has been little evidence of any advantage in this respect due to the ahemeral regime. 4. There was a marked correlated decrease in egg weight in both flocks.