This master's thesis aimed to examine the differences between breeds of gilts and the effect of their previous social experience on their response in a feed challenge test (challenged by not giving access to the feed provided in the feed stall promptly). The test was performed in their home group pen approximately 2 weeks before they gave birth to their first litter (at 8-9 months of age). The 65 gilts to be determined were between the two gilt breeds, and they were also exposed to two different social experiences (Early and Late social experiences). The results show that Swedish Yorkshire gilts were more exploratory and engaged more socially during the feed challenges test than Dutch Yorkshire gilts, suggesting that breed-specific tendencies, shaped by their historical breeding practices, affected their behaviour. Moreover, this research also emphasizes the impact of previous social experiences of gilts on their future behaviours. The gilts introduced to additional social mixing at 10 weeks of age exhibited aggressive behaviours of either a competitive or dominant nature compared to the gilts without that additional social mixing experience. This indicates the possibility that the previous social experiences will not only shape each gilts' behaviours but also affect their welfare and group interactions. The results of this thesis suggest that a deeper understanding of breed-specific behaviours and the impact of previous social environments can guide more welfare-oriented breeding, housing, and management strategies.