Thirty lactating Comisana breed ewes were used for the trial and were subdivided into 2 experimental groups. Both experimental groups were placed on pasture during daylight hours and reared in 2 equal indoor pens during nighttime. The indoor pen was provided with an outdoor area allowing 2.5 m2 per head and was always available during nighttime housing. During the experiment, the density of indoor pens varied weekly, whereas the outdoor area did not change. The indoor stocking densities tested were low stocking density (1.5 m2 per ewe), medium stocking density (1.0 m2 per ewe), and high stocking density (0.5 m2 per ewe). Throughout the trial period, indoor experimental pens were provided with unlimited access to water and a consistent number of feeding places at troughs equal to the number of ewes in the pen. Each density test lasted 7 days. The first 5 days were used to allow adaptation to experimental conditions. During the last 2 nights (sixth and seventh day), we recorded behavioral patterns. Jugular vein blood samples were taken to determine the hematologic and biochemical profile. Ewe milk yield was recorded on the seventh day, and individual milk samples were analyzed for milk composition, renneting properties, and somatic cell count. All the experimental activities were performed during winter and summer seasons to evaluate the effect of both seasons and space allowance on all parameters considered. No effects of space allowance and season were observed on hematologic and biochemical parameters (P > 0.05). During summer, animals spent more time in external areas, and this time increased with the reduction of space allowance. Ewes spent more time standing (P < 0.001) and less time lying down (P < 0.001) during the summer. During winter, in contrast, ewes did not use external area, but they spent more time standing and less time lying down in the indoor pens (P < 0.001). Milk production was poorly affected by stocking density. However, these results suggested that behavioral measurements seem to be more sensitive for the detection of stressful conditions as compared with other commonly used measures like endocrine, biochemical, or productive indicators of welfare in short-term stocking increase.