Increasing feed efficiency in swine is important for increasing sustainable food production and profitability for producers. However, it is unknown if selection for improved feed efficiency impacts the expression of sickness behavior. The objective of this study was to characterize gilt behaviors and postures when challenged with lipopolysaccharide (LPS). This work was conducted with 7 low residual feed intake (LRFI; more feed efficient) and 8 high RFI (HRFI; less feed efficient) gilts (63 ± 4 kg BW) from the 8th generation of the ISU Yorkshire RFI selection lines. All gilts were individually housed in metabolism crates. Gilts were challenged I.M. with 30 µg/kg BW Escherichia coli O5:B55 LPS at 10:00 ± 1 h. Gilts were video recorded one day before LPS challenge (baseline) and on the treatment day (LPS challenge). Video was analyzed using a 1-min scan sample interval at 2 time points; 1) for 2 h starting at the time of treatment injection and 2) for one hour starting at the evening feeding time (~17:00h). Standing, sitting, lying, eating, and drinking were recorded. Data were analyzed using the GLIMMIX procedure of SAS. The model included line, treatment, time, and the interaction, with a random effect of pig nested within replicate. There was no line by treatment interaction for behaviors and postures (P ≥ 0.32). There were no selection line behavioral and postural differences in response to the LPS challenge (P ≥ 0.45). Regardless of selection line, after the LPS challenge gilts laid more (P < 0.0001) and stood less (P < 0.0001). For the other behaviors and postures there were no treatment differences (P ≥ 0.16). In conclusion regardless of divergent selection for RFI, the LPS challenge affected lying and standing behavior in gilts in the same way. This project was supported by USDA-AFRI Grant no. 2011-68004-30336.