This paper addresses some of the health and economic concerns when dairies expand by internal herd growth and purchasing new animals. Recent research has shown that increased stocking density leads to decreased milk production, decreased reproductive performance, and increased lameness incidence. The limit of animal stocking density during an expansion must be carefully monitored to reduce animal illness, ensure economic profitability, and provide adequate facilities for the animals. Surveyed dairy producers admit to decreasing their biosecurity when purchasing animals for quantum growth. Appropriate vaccinations and quarantine will help reduce disease outbreaks. A combination of internal herd growth and purchased animals can be an appropriate method for dairy expansion.