Reports on the effects of mixing mated gilts to form stable, fixed groups during the pre-implantation period on conception rates and/or embryo survival are scarce. Consequently, the current experiment had two objectives: first, to investigate whether group housing during the first 4 weeks of gestation impairs embryo survival; second, to determine the effects of regrouping, and the timing of regrouping, during the first 10 days of gestation, on embryo survival. This experiment was conducted at the University of Adelaide, Pig and Poultry Production Institute (PPPI) at Roseworthy, South Australia, with approval from the animal ethics committee of The University of Adelaide. The experiment used 96 gilts, and was conducted in two replicates: replicate one ran from September to December 2006 (spring/summer) and replicate two ran from February to May 2007 (summer/autumn). It was found that group housing gilts during the first 26 days of gestation does not adversely affect pregnancy rates or embryo survival. Importantly, based on the current data, it is suggested that mixing gilts to form stable groups during the first 10 days of gestation is not detrimental to reproductive performance. However, the effects of remixing during the implantation period remain to be established, and the impact of mixing gilts under conditions when space is more limited is unknown.