Considering the permanent risk of introducing Avian Influenza (AI) in the state of Santa Catarina (SC), it is of fundamental importance to structure a very efficient Surveillance System (SS) for early detection of AI, and a capacity for appropriate reaction, in the form of implementation of emergency health measures to contain the spread of the disease and restore free status as quickly and at the lowest possible cost. Thus, to improve the contingency measures, in case the disease enters the state, we propose a mathematical model of the SIR type, stochastic, capable of simulating the spread of AI in time and space in a biologically plausible way, from different forms of introduction. The western region of SC, with a greater density of poultry properties, proved to be of critical importance if the disease is introduced. Simulations allowed conjecturing economic losses resulting from the entry of AI in commercial farms in the state. This SIR model constitutes a valuable resource for 1) defining SS characteristics for early detection of AI; 2) planning contingency actions, in case AI is introduced in the state; 3) training the teams that will manage the health emergency in function of the introduction of AI in the state; 4) and to carry out simulations of the economic impact in case of the entry of AI in the state. Although it was developed for the state of SC, this SIR model could be useful for any state, country, or region that has strategic interests in the poultry industry.