A stochastic bio-economic farm model was developed to assess the impact of innovations on pig farm performance. The model accounts for emissions of greenhouse gases by using the shadow price of CO2 and for stochastic prices. The model was used to assess the impact of using co-products in pigs’ diets on private and social profits for a typical Brazilian farrow-to-finish pig farm. The results show that social profits are 2.2-3.6% lower than private profits in all the standard and alternative cases. The stochasticity of profits is large (with coefficients of variation 52% to 61%) following from the volatility of prices.