<![CDATA[This study compared the production performance of broiler chickens reared in closed-house and open-house systems on partner farms of PT Ciomas Adisatwa in Tenggarong Seberang District, Kutai Kartanegara Regency, East Kalimantan. Data covered three rearing periods per system between December 2024 and February 2025, using Lohmann MB 202 birds harvested up to 35 days of age. Feed consumption, harvest weight, daily body weight gain, feed conversion ratio (FCR), mortality, and performance index (PI) were recorded. Each system was represented by three periods (n = 3) and compared with a two-sample t-test. Welch's test, mean differences with 95% confidence intervals, Hedges' g, and Holm correction were added to assess the precision of the estimates. Mortality was lower in the closed house (2.83 ± 1.26% vs 5.47 ± 0.91%; P = 0.042) and PI was higher (403 ± 12 vs 358 ± 25; P = 0.048). Neither difference remained after Holm correction (P = 0.254), and the PI difference was not significant under Welch's test (P = 0.073). FCR (1.507 vs 1.564), feed consumption (3,019 vs 3,129 g/bird), and harvest weight (2.05 vs 2.00 kg) did not differ significantly (P > 0.05). Per 1,000 day-old chicks, the closed house yielded about 26 more surviving birds and 98 kg more live weight. The closed house tended to perform better in mortality and PI, but three periods per system are too few to confirm the difference. Follow-up studies need farm-level replication and recorded microclimate data.]]>
