Purpose. The development of a computer program for choosing the optimal variant of economically feasible production during the reconstruction of premises with the simultaneous transfer of pig breeding from a round to a flow system for receiving farrows. Methods. The following methods and techniques were used during the search work: zootechnical, monographic, comparative, calculation-constructive, mathematical, abstract-logical, and computer modeling. The results. It was determined the fact that there is a direct relationship between fertility, the duration of rearing and fattening, and the number of machines for housing animals, and an inverse relationship with a simultaneous increase in fertility, a decrease in technological waste, and a shortening of the fattening period due to an increase in the level of average daily gains and the required number of machines. It has been confirmed that the use of computer modeling tools when changing the values of the step of the production rhythm, the number of sows in the step group, their fertility, the preservation of offspring, the intensity of growth, allows to determine the consequences of the influence of these changes, and the comparison of the results of several calculations with each other allows to choose and propose real, not desired values of production indicators that will be able to ensure uninterrupted and profitable production of pig breeding products for a long time. The use of the developed software made it possible to optimize the distribution of the production area for the placement of machines for animals of different technological groups, based on the duration of the rhythm step, the number of sows and offspring, the preservation and intensity of growth during the period of rearing, fattening, and the duration of the animals' stay in these sections. The use of developed software allows to quickly form a detailed business plan based on real, not desired values and allows to obtain a positive balance between the sales value of the manufactured products and their cost price, where a significant share is the cost of feed, water, energy carriers, etc., and they depend on the total number of animals in technological and step groups, from the duration of the animals' stay in rearing and fattening. Errors in calculations can cause significant financial losses. Conclusions. The computer modeling of the production process by repeatedly changing the values of the input indicators allows to quickly calculate the likely consequences and choose from many options those that will maximally correspond to the productivity of animals and the capabilities of the farm and, and during their implementation, they will allow to ensure uninterrupted and profitable production of pig breeding products. Key words: pig breeding, applied programs, computer modeling, technology, tour and flow farrowing system, productivity, reconstruction.