To evaluate the horizontal intraspecies transmissibility of the two novel H5N6 viruses, three SPF chickens were intranasally inoculated with 0.2 mL PBS and introduced into the same cage as a naïve contact group, which were then housed with chickens inoculated with SW8 or ZH283. Shedding of SW8 could be detected from both oropharyngeal and cloacal swabs within 3 DPI, with viral titers in the ranges of 2.42–3.83 log10EID50 in oropharyngeal swab samples and of 1.52–3.79 log10EID50 in cloacal swab samples. ZH283 could also be detected from oropharyngeal and cloacal swabs within 5 DPI, with viral titers in the range of 4.58–4.75 log10EID50 in oropharyngeal swabs and of 3.50–3.90 log10EID50 in cloacal swabs (Figures 2A,B). Naïve contact chickens co-housed with chickens inoculated with SW8 did not die during the observation time, but all contact group chickens seroconverted and exhibited high titers (9.33 ± 0.58 log2), as shown in Table 2. Viral shedding was observed in both oropharyngeal and cloacal swabs, and viral titers of 1.50–1.83 log10EID50 within 5 DPI were detected in oropharyngeal swabs (Figure 2A); however, viral titers of the cloacal swabs could be detected (1.08 log10EID50) at 3 DPI (Figure 2B). Naïve contact chickens co-housed with chickens inoculated with ZH283 exhibited 100% lethality and mortality, with a MDT of 5.0 days (Table 2), and exhibited clinical signs of illness, including coughing, cloudy eye, and dyspnea. All surviving chickens in the naïve contact group co-housed with ZH283-infected chickens shed virus from the oropharynx and cloaca within 7 DPI, with mean viral titers of 2.75–3.75 log10EID50 in oropharyngeal swabs and of 1.75–4.50 log10EID50 in cloacal swabs (Figures 2A,B). In short, results demonstrate that the two novel H5N6 influenza viruses replicated efficiently in chickens and exhibited efficient transmission via direct contact in the chicken model.