## 4 Discussion
In addition, the results support those reported by [PERSON] [18], who observed 9% higher egg mass in AM/PM hens compared with control hens. The higher egg mass may be also attributed to heavier egg weight due to the intake of a protein-rich diet in the morning [35]. Hens offered AM/PM feeding had 6.45% lower feed intake and 8.34% lower FCR compared with conventional feeding in the current study. This indicated that the patternof AM/PM feeding adjusted the quantity of feed nutrients proportionally according to the demands of the egg formation cycle and thus enhanced feed efficiency. The findings are in agreement with [PERSON] [18], who reported that feed intake of laying hens decreased by 16.1% and FCR improved by 25% when diets were presented with higher protein/energy and lower Ca in the morning and lower protein/energy and higher Ca during afternoon/evening. In addition, an earlier study by [PERSON] et al. [14] showed that feed efficiency was improved in hens who received low protein/energy and high Ca diets 8 to 10 h post oviposition, which may also correspond with the current findings. Thus, feeding AM/PM diets could be auspicious to improve economic efficiency in layer farms. However, the variations in the outcomes of intensity, compared to the previous study conducted by [PERSON] [18], could be attributed to the fact that their study was carried out during the later phase of the laying cycle (53 to 68 weeks). This implies that the AM/PM feeding strategy might exhibit more potential benefits during the late production cycle or in increasing hens' laying cycle. Consequently, additional research is warranted to delve further into these possibilities. To produce an egg, a laying hen requires around 2.2 g of Ca [36]. Approximately two-thirds of this Ca is derived from the diet, while the remaining one-third is sourced from the medullary bone [36]. The process of Ca ingestion and its deposition in bone occurs during the daytime, with subsequent mobilisation from bone and mineralisation into the eggshell taking place at night. It is speculated that ensuring accessible Ca from the PM diet for hens during the eggshell formation phase can contribute to improved eggshell quality. However, this study did not observe any improvements in eggshell quality following AM/PM feeding. In a prior study, providing hens with the majority of daily Ca in the afternoon also did not increase shell quality when compared to the control group receiving a diet with 3.5% Ca in both the morning and afternoon [22]. The impact of dietary Ca level on eggshell formation is contingent on the overall Ca intake during calcification [16]. In this study, hens receiving AM/PM diets consumed less feed than the control group. This may partly explain the less pronounced effects on eggshell quality observed in the current study. However, the provision of higher dietary Ca levels in the afternoon may have an impact on eggshell quality in older hens, particularly when the replenishment of Ca from the medullary bone becomes less accessible during egg formation, necessitating further exploration. There were also no visible effects on other egg quality traits except the higher yolk colour scores in eggs laid by AM/PM hens compared with the control hens. Other studies also observed no effects on egg quality when diets were split into different parts of the day [20; 34; 37]. The higher yolk colour score in AM/PM eggs may be due to higher consumption of materials from the range during ranging, which contain natural pigments such as insects, plants, flowers, and grasses compared with the control hens. This is supported by the results of the complementary part of this study, which showed AM/PM hens spent a longer time ranging outside relative to the control hens [38]. Additionally, previous studies have also reported that hens spent more ranging time outside produced eggs with a darker yolk colour [39; 40]. In this study, hens fed the AM/PM diets had lower digestible energy and digestible N compared with those offered the conventional diet.