## 4 Discussion  
Least-cost feeding strategies have sparked keen interest in the egg industry due to sharp increases in feed ingredient prices in recent years [5; 30; 31]. Understanding hen physiological and nutritional requirements, and tailoring diets accordingly, could reduce feed costs. Findings from the current study showed that feeding a high protein and energy and low Ca diet in the morning, followed by a low protein and energy and high Ca diet in the afternoon/evening is more economically beneficial compared with feeding an average diet for the whole day. The current findings also showed that AM/PM feeding increased feed efficiency and the yolk colour score, although the quality of the eggshell did not exhibit the expected results to support the hypothesis. In the present study, the AM/PM feeding regimen was found to have no impact on the hens' weights but tended to improve uniformity in egg weights, indicating that this approach meets the hens' physiological growth demands without adversely affecting egg size. This finding corresponds with those reported by [PERSON] [18], which indicated that protein and energy levels in afternoon/evening diets do not need to be the same as those in morning diets to maintain hen uniform body weight and growth. In the AM/PM feeding strategy, hens receive their morning diet after oviposition and yolk formation. The yolk requires the deposition of albumin (i.e., protein), while energy plays a pivotal role in sustaining hen physical activity including ranging on the outdoor range after oviposition [10; 11]. Thus, the better egg weight uniformity of AM/PM hens in this study could be attributed to the availability of the required nutrients when they are actually needed. The trend indicating increased egg production in hens fed the AM/PM diet during the first 10 weeks, not the second 10 weeks, in this study may be due to the hens' physiological and genetic characteristics. Hens reach peak production around 35-37 weeks, then egg production decreases gradually after that [32]. Thus, we would most likely see the effects of AM/PM feeding on egg production during the earlier stage of this study rather than the latter. Also, it may be worth noting that the egg production of both the AM/PM and control treatments over 20 weeks of this study was high (94-95%) compared with the Hy-Line Brown performance standards. The hens used in this study may have already reached their genetic potential, and there may not have been much chance to improve egg production further. Some other studies also did not find a significant impact of AM/PM feeding on egg production as observed in the 20-week findings of the current study [21; 33]. Moreover, significantly higher feed consumption by the control hens compared with the AM/PM group from 44 to 53 WOA might ensure persistency in egg production, and thus, no effect was observed when comparing the results for the entire duration. However, during peak production, nutrient levels for hens need to be optimised for the high rate of production. If peak production remains consistent for a longer period, it is advisable to adjust Ca and phosphorus concentrations to those of the next feeding phase [32]. Adjustment of feeding timing for the required nutrients through AM/PM feeding in that time may add some value to enhance the production rate [34]. This might support other studies [18; 20] where hens under split feeding showed a tendency to increase egg production more than those offered a conventional diet. Thus, the AM/PM feeding strategy may increase egg production during the later phase of the production cycle and could have the potential to increase the laying cycle, warranting further investigation. This study did not find an effect of AM/PM feeding on egg weight, but egg mass was observed to be 2.15% higher during the first 10 weeks with an overall increasing trend compared with the control diet. This is consistent with the present study findings that AM/PM hens had a trend of producing uniform and heavier eggs than control hens.