## 1 Introduction  
The air quality inside facilities dedicated to animal production is an essential factor to guarantee the health and comfort of the animals and producers [1, 2, 3]. In modular facilities for rabbit production, the most important environmental variables are temperature, humidity, and emissions of harmful gases [4]. A temperature between 25 and 30 \({}^{\circ}\)C increases the heat load on rabbits; above 30 \({}^{\circ}\)C the effects are a decrease in food consumption and fertility rate, affecting the production yield [5]. Rabbits are susceptible to heat stress given that the number of functional sweat glands they have is not sufficient to eliminate excess body heat [5]. Heat stress is a combination of an increase in temperature and the consequent decrease in humidity. The temperature-humidity index indicator has been used, whose parameter has been modified and used in rabbits [5, 6]. Ammonia (NH\({}_{3}\)) has an effect on soil acidification, along with the emission of particulate matter and nitrous oxide [2, 7]. The emission of gases from livestock and agricultural activities contributes to the greenhouse effect, since they are the main source of NH\({}_{3}\) emission and, especially in rabbits, it is the cause of respiratory diseases [4, 8]. There is a correlation between the indoor climate of a farm and the comfort of the inhabitants, which is why it is necessary to expand the analysis of the climate dynamics within the area occupied by the animals as a response to the ventilation system [9]. The ventilation of a livestock facility is a phenomenon that allows for the management of variables such as temperature, humidity, and gas concentrations. Research has been carried out on the ventilation system of a livestock facility, using methods such as direct measurements, the application of Bernoulli's theorem, sum of volume flow rates, tracer gas, and computational fluid dynamics (CFD) techniques [10]. Computational fluid dynamics is a tool used for modeling livestock facilities; it includes potential possibilities to simulate important conditions that can influence the indoor climate in a livestock facility [11]. Among the research studies that have been carried out using computational fluid dynamics are the following: in pig farms, air velocity analysis [11; 12], temperature and heat stress studies [13; 14], studies of ammonia emissions [15; 16], and those focused on dust generation within the installations [3]; in cattle facilities, studies of heat transfer [17; 18], ventilation rate [19], and extensive studies on air velocity and its influence on temperature, humidity, and heat transfer [20], as well as studies on the emissions of gases such as methane and ammonia, as well as CO\({}_{2}\) and N\({}_{2}\)O [1; 7]; in bird houses, there have been studies that model the indoor climate and heat emissions [21; 22; 23] and simulations on air flow, temperature, humidity, and ammonia emissions [24; 25; 26]. However, in rabbit farms there have been few studies: one study performing simulations to determine the temperature gradient and ammonia concentration [27], and a study on the distribution of the air flow of the indoor environment in a rabbit facility [28]. A critical factor in rabbit farm operation is climate control. The particularity of this species is that their own feces contain bacteria that, when breathed, produce methane, a toxic gas even for the rabbit. Methane production occurs \"per ze\" and increases mainly depending on temperature and humidity. When the methane reaches the level of the cages, the rabbit breathes this gas causing cyanosis, fever, lack of appetite, and sometimes death. Natural ventilation is the minimum strategy to maintain temperature, humidity, and toxic gases at levels suitable for the rabbits. Using numerical simulations based on computational fluid dynamics allows, in the first instance, the identification of the situation that prevails in the farm environment.