Avian pathogenic Escherichia coli (APEC), a subtype of extraintestinal pathogenic E. coli (ExPEC), is a major causative agent of avian colibacillosis, leading to substantial morbidity and mortality in poultry, incurring enormous economic losses and threatening global food security. Moreover, the zoonotic potential of APEC raises public health concerns. The growing threat of antimicrobial resistance has prompted a shift toward developing alternative intervention strategies that support gut health and productivity without contributing to antimicrobial resistance. One promising approach proposes to use Lactiplantibacillus plantarum (LP), a probiotic lactic acid bacterium with immunomodulatory effects and potential as a live vaccine platform due to its capacity for heterologous protein expression.  Genome-wide association studies combined with reverse-vaccinology tools have enabled the identification of genes encoding potential candidate antigens with the capacity to confer broad cross-protection against APEC infection. Selected candidates were cloned into three LP isolates on plasmids under a constitutive promoter, to generate candidate APEC vaccines. Using an in vitro model of the chicken caeca, we demonstrated that one of the promising LP isolates was able to integrate into the resident chicken caecal microbiota and be maintained for up to 120 hours. Moreover, all three isolates exhibited resilience to gastric acids and bile salts, indicating their potential as orally administered vaccine vectors.  These findings highlight the potential of novel APEC vaccines and innovative vaccine platforms, such as Lactiplantibacillus plantarum, for the safe and effective antigen expression to produce vaccines against APEC and other poultry diseases.