Growth is a key characteristic of animals and can be defined as any change in body size per time unit, and is influenced by genotype and environment. Mathematical functions called ‘growth models’ have been used to explain the growth patterns of poultry species. These semi-mechanistic growth models have a non-linear structure, sigmoid shape, and certain biologically meaningful parameters. In poultry science, Gompertz, Logistic, Richards and von Bertalanffy functions have been commonly used to model the growth patterns of birds. In this review, the studies concerned have been summarised under the titles ‘determination of the best-fitting growth model’, ‘a comparison of the growth of poultry species or various experimental groups’, and ‘genetic parameter estimates for growth curve parameters’. This review discusses existing and new approaches to growth modelling.