Do you believe that the sheep in Matthew 25:46 are given eternal life in the sense that they are saved, but remain in physical bodies to populate the millennium? Or that they are given resurrection bodies? I believe its the first option.
I believe they (at that context/setting) [the still-living ones (which is what I believe the CONTEXT of Matt25:31-34 pertains to)] are given eternal life, enter the MK in mortal bodies capable to reproducing/bearing children (in the MK time period) but also that they "SHALL NEVER DIE" because of what Jesus had said in John 11:25-
26 (Jesus, Who is "the Resurrection" AND "THE LIFE," will be present and ruling/reigning there--death will be much more rare in the MK, reserved only for the rebellious). The ones that die during the trib will be "resurrected" [also re: saints, of course] and thus have resurrected bodies (not ones to bear children in the MK).