This paper reports the results of economic analysis of the effects of floor space and feeder space on broiler chicken growth rates. First, liveweightffeed conversion rates are described and a function fitted. Use of conversion efficiency functions for determining optimal space inputs in the production process would be appropriate where feed cost considerations are dominant. Second, use of more orthodox response surface analysis permits specific consideration of marginal productivities of floor and feeder space inputs. Optimal input levels (i.e., stocking rates and feeder space allocations) and profit margins are developed parametrically for a range of input costs and liveweight prices.