Data obtained from 4 different capacity houses were evaluated to analyse the cultural energy and performance of broilers. Capacities of housings were 20,000, 25,000, 30,000 and 60,000 birds per production period and they were assigned as HI, HII, HIII and HIV, respectively. The study was conducted in 2005 in which there were 6 production periods of 45 days. Data collected for each period were: date of starting and finishing; number of chicks entered and broilers sold; live weight at slaughter; carcass weight; feed consumption for starting, growing and finishing phase; labour; medication, vaccination and disinfectant; electricity consumption; heating and cooling methods and amount spent; distance for transportation of feed, chicks, broilers, wood shaving, limestone; and other miscellaneous expenditures. Ross 308 chickens in all houses received the same commercial feed and water ad libitum. Chicks were reared under a conventional temperature regimen. Chicks were fed starter, grower and finisher diets according to their ages. Even though capacities for houses were different their stocking densities were 16.36, 16.00, 16.38 and 16.54 birds/m(2) for HI, HII, HIII and HIV, respectively. For cultural energy analysis, feed, transportation, labour, machinery, electricity, brooding, and other inputs were calculated and corresponding energy values for each input were obtained from literature. For the analysis it was assumed that carcasses would have 18.2% protein and 15.2% fat. Total cultural energy invested in broilers in HIII was lower than that of broilers in HI (P < 0.05). Energy input per kg live weight gain and per kg carcass of HIII were lower than that of HI (P < 0.05, P < 0.01, respectively). The HIII had lower cultural energy ratio for protein energy output than HI (0.01). Energy efficiency (kcal input/kcal output) of HIII was better than that of HI (P < 0.01). Results of the study showed that increasing capacity of housings decreases cultural energy input up to certain capacity and indicated that increasing housing capacity without interfering with performance could be a means for energy conservation in sustainable agriculture.