Plasma volume and electrolytes during progressive water deprivation in chickens (Gallus domesticus).

1. Studies were performed to examine the effects of progressive water deprivation in the fowl (Gallus domesticus). 2. A reduction in plasma volume and an increase in capillary permeability to protein were observed only after 3 or 4 days of dehydration. 3. Moderate changes in arterial blood pressure and heart rate were noted in dehydrated birds but respiratory rate and body temperature remained unchanged. 4. Dehydration was associated with increases in the concentration of total solutes, sodium and chloride in plasma but no changes were noted in plasma potassium levels or arterial pH. 5. The results indicate that the chicken can maintain volume more effectively during water deprivation than several mammalian species.