Whole blood biochemistry and blood gas analysis are uncommonly used in poultry, but their use could improve the diagnosis of certain diseases or aid in monitoring flock health. To create preliminary reference intervals for selected blood analytes in broilers using the i-STAT and Vetscan VS2 (VS2) portable analyzers, we tested broilers at 7, 21, and 35 days of age. A total of 134 venous blood samples from healthy chickens of two different flocks were analyzed. There were significant age-related increases in concentration for glucose, hematocrit, ionized calcium, sodium, and carbon dioxide partial pressure on the i-STAT and for aspartate aminotransferase, creatine kinase, total calcium, phosphorus, and total protein on the VS2. Conversely, significant decreases in concentration were observed for pH, oxygen partial pressure, oxygen saturation on the i-STAT and for uric acid and albumin on the VS2. Additionally, significant differences were found on some blood parameters among the two flocks. Extremely high CK values were found on broilers after 21 days of age, indicating a possible degree of muscle injury during the grow-out. Preliminary reference intervals for all the analytes at each of the age groups were obtained. This study's data provide a starting point for the interpretation of blood analysis in broiler chickens at different ages and offer a new approach to investigate certain metabolic diseases that affect commercial poultry.