An experiment was done to evaluate the effects of diet nutrients density on performance and egg quality in laying hens during the post-peak production phase of the first laying cycle under subtropical climate. A total of 768, 49-weeks-old Hy-Line-W36 laying hens were assigned in a completely randomized design with six treatments, eight replicates, and 16 birds each. Experimental treatments were given the diet with nutrients density recommended by the Hy-Line-W36 guide for their age and level of production (100%) or were given 92%, 94%, 96%, 98%, and 102% of that. During the experimental period, the average ambient temperature and humidity were 27.41±2.54°C and 35±5%, respectively. By increasing diet nutrients density significantly improved egg production (EP), egg weight (EW), egg mass (EM), feed conversion ratio (FCR). Also, egg crude protein and yolk ether extract composition, egg special gravity and relative shell weight significantly increased as increased diet nutrient density. Average bird’s daily feed intake (FI), egg shell thickness, Haugh unit and solid percentage did not affect by diet nutrients density. By linear broken-line models, the diet nutrients density for optimized EP, EM, and FCR were estimated at 97.93%, 97.57%, and 100% of strain recommendation, respectively. It is concluded, laying hens during the post-peak production phase of the first laying cycle and under subtropical climate was not able to adjust FI with diet dilution. Nutrient requirements varied to what productive parameter was taken for optimization. Optimum FCR was achieved when the diet was formulated to followed strain recommendations.

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