The ability of France to meet its European Union commitments to decreasing ammonia emissions requires better knowledge of concentrations in all sectors, including the pig sector. Thus, measuring equipment should provide reliable data and be easily used on farms. The aim of this study was to compare three types of measuring equipment used in a fattening room of Ifip’s experimental farm. The room housed 54 pigs that weighed ca. 50 kg each, were kept on a fully slatted floor and had their slurry stored in a pit below the floor. The three types of equipment were an infrared photoacoustic analyser (Innova 1512, Lumasens Technologies, Denmark) that continuously measures ammonia, N2O, CH4 and CO2; an opto-electronic nose (NeOse Advance, Aryballe, France) with a silicon-based optical sensor; and an ultraviolet (UV) spectrophotometer (G800, Hemera, France) that uses the spectral signature of ammonia. Each type of equipment was placed in the middle of a pen at ca. 1.8 m high and operated for 20 hours. The mean concentration of ammonia measured by the infrared photoacoustic analyser was 3.0 ± 0.6 ppm, which agreed with that observed previously under the same conditions and in the literature. The mean concentration measured by the opto-electronic “nose” and the UV spectrophotometer differed little: 2.5 ± 0 and 2.4 ± 0.8 ppm, respectively. These two types of equipment appeared more adaptable to measurements under commercial conditions than the gas analyser currently used for research on gaseous emissions from pig production.