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Abstract
1. Pullets allowed to self‐select nutrients from a protein concentrate and either a separate complete diet or cereal‐based, energy‐rich mixture showed preferences for protein and energy which varied in relation to the time of their onset of lay.
2. The selected protein: metabolisable energy (ME) intake ratio increased from 14 g protein per MJ of ME 2 to 3 weeks before sexual maturity to approximately 19 g protein per MJ of ME at and after sexual maturity.
3. This response to self‐selection feeding was consistent with different temperatures, lighting patterns and dietary manipulations.
4. Egg mass output was improved by self‐selection feeding at hot (25° to 35°C) temperatures in experiments 1 and 2 and at ambient temperatures in experiment 3. No beneficial response in egg mass from self‐selection feeding was observed at cold (6° to 16°C) temperatures in experiment 1.
5. Providing 2 h of additional light during the dark (cool) part of the day, with or without 2 h of darkness in the middle of the extended light (hot) period, had no effect on the egg mass output of pullets at hot (25° to 35°C) temperatures.
