An experiment with 250 day-old Ross male broilers was conducted to investigate the differences of blood gas parameters, internal organ weights and perfosrmance of cold induced ascitic and healthy broilers in a 6 week period. These chickens were divided to two groups of 5 replicates each. One group of these chickens was bred in Normal Temperature (NT treatment) but other group was set in Low Temperature (LT treatment) to induce ascites. Body Weight Gain (BWG) and Feed Intake (FI) were measured weekly. Blood gases analyses were measured from day 14 afterwards. Mortality was necropsied daily to determine cause of death. At the end of the experiment, 5 chickens from each replicate were randomly selected, weighed, slaughtered, heart was removed and its parts weight determined. Moreover weights of liver, lung, gut (empty weight) and spleen were assayed. The results of blood gases analyses showed that pH, bicarbonate and pCO2 were similar for two groups, while pO2 of LT group was lower (p 0.05) than that of NT group in weeks 3, 5 and 6. Also O2 saturation of LT group was lower (p 0.05) than that of NT in weeks 5 and 6. Despite of some differences between two treatments for internal organ weights such as liver, lung, heart, empty gut and spleen weights, these differences were not significant. FI in first two weeks of age was similar for two groups then FI of LT group began to decrease when compared to NT group and at the ages of 3, 4, 5 weeks and all of the study period (6 weeks) FI was lower (p 0.05) than that of NT treatment. BWG of LT group at 4th week of age and total period of the study was lower (p 0.05) than that of NT group. Right Ventricle (RV) and RV to Total Ventricle (TV) ratio of LT treatment was greater (p 0.05) than that of NT group. Mortality caused by ascites in total period of study for LT treatment was significantly (p 0.05) higher than that of NT group (8.8 vs 2.4%). Under the conditions of this study it was concluded that inducing ascites by decreasing temperature may impact performance and changes pO2 and O2 saturation of broiler chickens.

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