Venoms are complex mixtures of biologically active molecules that impact multiple physiological systems. Manufacture of antivenoms therefore requires potency testing using in vivo models to ensure antivenom efficacy. As part of ongoing research to replace small animals as the standard model for antivenom potency testing, we developed an alternate in vivo method using the embryonated egg model (EEM). In this model, the survival of chicken embryos envenomated in ovo is determined prior to 50% gestation, at which point they are recognised as animals by animal welfare legislation. Embryos were found to be susceptible to a range of snake, spider, and marine venoms. This included funnel-web spider venom for which the only other vertebrate, non-primate animal model is newborn mice. The exploration of this model with additional Australian and exotic venoms and toxins is continuing and will be discussed. Neutralisation of venom with standard antivenom allowed correlation of antivenom potency results from the EEM to results from animal assays. Our findings indicate that the EEM provides an alternative, insensate in vivo model for the assessment of antivenom potency. The EEM may enable reduction or replacement of the use of small animals, as longer-term research that enables the elimination of animal use in potency testing continues.