This invention relates generally to animal models of anxiety and depression. Specifically, this invention relates to an in vivo high utility, high-throughput model for screening anxiolytic/antidepressant drugs in fowl chicks with stress vulnerability. This new animal model utilizes an inexpensive avian model, measures spontaneous behaviors in very young animals, and is capable of detecting and/or differentiating a compound's anxiolytic and/or antidepressant effects. This new animal model is especially useful in detecting and/or differentiating a compound's anxiolytic and/or antidepressant effects in treatment-resistant subjects. Animal costs are less than 10% of rodent costs and the assay can be run in a high-throughput mode.