This study intended to compare the productive performance of three different layer raising systems; conventional cage (CC), barn (BR) and aviary (AV). The AV is welfare bestowed housing that allows free locomotion for birds within the BR. The BR allows bird's free locomotion inside BR but without multilevel structures. Both pullets and cockerels were housed together in both AV and BR, but only pullets in CC. Seventeen weeks old Lohmann Brown Lite (n = 800) pullets were housed in AV during this study. The same age layer pullets were simultaneously assigned to either at CC or BR to compare egg production performance with AV. The duration of experiment was 40 weeks (from 21st to 60th week). There were no remarkable differences in egg production, hen day egg production (HDEP) and average egg weight among three rearing systems. First 20 weeks (phase-1) average HDEP (%) of AV, CC, and BR were 85.9, 88.8, 87.1 and average egg weights (g) were 57.5, 59.9, and 56.9 respectively. Those of the remaining 20 weeks (phase-2) were 87.1, 87.9, 85.5 and 64.2, 63.0 62.1, respectively. Daily feed intakes (122 g, 110 g, 125 g); feed conversion ratio (2.4, 2.1, 2.5) and daily egg mass (53.9 g, 54.4 g, 52.8 g) data from AV, CC, and BR were not influenced significantly by the respective raising systems. Daily feed intake of layers in both AV (124 g) and BR (127 g) tended to be higher than that in CC (113 g) during phase-2. Overall, exterior egg quality (dirty and cracked eggs) in both phases was superior in BR compared with AV and CC, whereas CC generated intermediate results. This study indicated that the HDEP per se in AV and BR were not significantly different from that in CC. The study implied that the facility depreciation cost for AV and cost for increased feed intake in AV compared to CC are believed to be critical to evaluate the cost effectiveness of egg production in AV.

Growing global demand for poultry products continues to intensify pressure on conventional feed ingredients, particularly soybean meal and fishmeal, which face sustainability, cost, and supply-chain constraints. Biotechnological and digital innovations are emerging as viable pathways for developing alternative protein sources that reduce environmental impacts while supporting efficient poultry production. This review synthesizes recent advances in single-cell protein, precision-fermentation products, insect-derived meals, microalgae, and upgraded agro-industrial byproducts, with emphasis on their nutrient composition, amino acid balance, digestibility, and functional bioactive properties. Special attention is given to improvements in growth performance, feed efficiency, immune responses, gut microbiota modulation, and meat quality observed in poultry fed biotechnology-derived protein. The review integrates evidence on environmental and economic benefits, including reductions in land use, water demand, and greenhouse gas emissions, as well as their contributions to a circular bioeconomy through waste valorization and nutrient recycling. Key regulatory, safety, and industry-adoption challenges are evaluated, particularly those related to large-scale processing, standardization of nutrient profiles, consumer perception, and approval pathways. Digital innovation is presented as a critical accelerator for next-generation protein development. Emerging tools such as artificial intelligence, machine learning, digital twins, automated bioprocess monitoring, and multi-omics technologies are described in relation to strain optimization, predictive modelling of nutrient digestibility, process control, quality assurance, and precision formulation. These technologies increase feasibility and reduce development time, making biotechnology-enhanced proteins more competitive with conventional feedstuffs. Overall, biotechnology combined with digital innovation presents transformative opportunities for sustainable poultry nutrition. The integration of engineered microbial biomass, insects, fermentation-enhanced byproducts, and data-driven feed optimization can improve production efficiency while reducing environmental burdens. The insights summarized in this review provide a foundation for researchers, industry stakeholders, and policymakers seeking to advance climate-smart, resource-efficient, and circular poultry production systems.