Background: The nutrient requirements of laying hens are not static but dynamic, changing throughout the day in response to the cyclic nature of egg formation. Objectives: The current study aimed to evaluate the impact of the AM/PM feeding regimen (AM/PM-FR) which involved higher levels of protein, amino acids, and available phosphorus, and lower levels of Ca in the morning diet, with the conversely in the afternoon diet on aged laying hens. Methods: A total of 300, 74-week-old Hy-Line W36 laying hens were randomly assigned to a completely randomized design with five treatments, six replicates, and 10 hens per replicate. Experimental treatments included offering AM/PM-FR at 0% (control), 10%, 20%, 30%, and 40% changing nutrient levels (CNL) between the morning (05:00 h to 14:00 h) and evening (14:00 h to 05:00 h) diets. The exposure program consisted of continuous lighting from 05:00 to 21:00 h and darkness from 21:00 to 05:00 h. Results: The feed conversion ratio (FCR) and economic profit, income minus feed cost (IMFC), improved with a quadratic trend in response to increased CNL of AM/PM-FR. Throughout the entire experimental period, birds fed AM/PM-FR at 30% CNL showed improvements of 4.57% in FCR and 17.55% in IMFC compared to the control group. A lower incidence of egg fractures and a higher yolk crude protein concentration were observed with a linear trend in response to increased CNL of AM/PM-FR. By increasing CNL of AM/PM-FR, the total tract apparent mineral (Ca and phosphorus) and ether extract retention improved with quadratic and linear trends, respectively. Non-significant effects of the treatments were noted on egg quality, blood metabolites, bone mechanical properties, and mineral contents. Conclusions: It was concluded that the use of AM/PM-FR at 30% CNL in aged laying hens may facilitate the precision nutrition and thus improve production and economic performance.

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