Background and Aim: The high cost and limited availability of maize in poultry production necessitate the exploration of alternative feed sources. Bread waste (BW), a nutrient-rich by-product, offers a sustainable substitute. However, concerns regarding its protein degradation during processing and limited research in laying hens restrict its broader application. Probiotics such as Bacillus amyloliquefaciens CECT 5940 may enhance nutrient utilization and economic viability when combined with BW. This study aimed to evaluate the effects of partially replacing maize meal with BW, with or without the inclusion of B. amyloliquefaciens CECT 5940, on the productive performance and economic outcomes in laying hens.

Materials and Methods: Sixty 52-week-old Lohmann Brown laying hens were randomly assigned to one of three treatments (n = 20 per treatment; 4 replicates of 5 hens each): (T1) basal diet; (T2) basal diet with 20% BW replacing maize; and (T3) basal diet with 20% BW and 0.8% B. amyloliquefaciens CECT 5940. Performance parameters and economic indicators, including feed intake, egg production, feed conversion ratios, gross revenue, contribution margin, and break-even point, were assessed over 45 days.

Results: No significant differences (p > 0.05) were observed in laying rate, egg mass, feed conversion per dozen eggs, or live weight across treatments. Economically, substituting 20% of maize with BW significantly reduced feed cost per kilogram and egg production cost per unit and per dozen (p < 0.05). The inclusion of B. amyloliquefaciens further enhanced the profitability index, gross value added, and reduced the break-even point compared to T1 and T2 (p < 0.05).

Conclusion: Replacing 20% of maize with BW, with or without B. amyloliquefaciens CECT 5940, maintains productive performance in laying hens while significantly improving economic efficiency. This strategy offers a viable and sustainable alternative to conventional feed formulations in poultry production.

Keywords: Bacillus amyloliquefaciens, bread waste, laying hens.