Resumen: The study analyses spatial preferences and behavioural patterns of lambs during fattening in straw enriched pens. Lambs were allocated in three replicates with 12 lambs each and housed in 6x6 m pens partially divided in two equal areas with and without straw bedding. Each pen was video-recorded continuously from 8 am to 8 pm on days 1, 5, 7, 14, 21 and 28. The use of different pen areas and the behaviour of the lambs were evaluated and analysed. The use of the space was significantly higher (p<0.05) for the straw area, where there was also more resting and affiliative interactions (p<0.05). In the areas without straw, animals walked more, remained standing longer periods (p<0.05) and had more stereotypic and aggressive behaviour (p<0.05). The study demonstrated that, when given the choice between two areas with similar resources, lambs prefer straw bedding. Straw is suggested to promote affiliation improving the adaptation to the feedlot. This could be useful to convince system managers that the availability of straw is beneficial to lamb welfare. Idioma: Inglés Año: 2015 Publicado en: Archivos de Zootecnia 64, 246 (2015), 155-160 ISSN: 0004-0592 Originalmente disponible en: Texto completo de la revista