We examined growth rates and physical development of four body characteristics (mass, wing chord, bill length, and head width) of Lesser Prairie-chickens (Tympanuchus pallidicinctus) 3 to 111 days post-hatch in southeastern New Mexico. Growth rates, inflection points, and selected growth curves (logistic and Gompertz) associated with body mass and wing chord were similar between Lesser Prairie-chickens in New Mexico and Kansas. The asymptotic body mass (713 ± 7 g) was less for female and male yearling Lesser Prairie-chickens in New Mexico than for either yearling females or males in Kansas (male: 789 ± 4, female: 719 ± 6). Juvenile Lesser Prairie-chickens in New Mexico achieved 90% of their asymptotic body mass 7 days faster than Lesser Prairie-chickens in Kansas.