This chapter focuses on the two main methods of measuring lateralized information processing and lateralized behavior control in young domestic chicks: temporary monocular occlusion and spontaneous eye preferences. Domestic chicks represent the main animal model to study the ontogenesis of functional visual lateralization. These techniques can be applied to investigate a variety of experimental questions, in studies investigating phenomena as disparate as early social predispositions, filial imprinting, social learning, spatial memory, and numerical cognition. Here, we exemplify the types of inferences afforded by employing monocular occlusion or by measuring eye preferences in the context of these tasks. We then conclude with a comparison of the advantages and disadvantages of these two simple yet powerful procedures.