I use sleepers around the edges of ponds and when there is a couple of inches of snow on the ground and it is COLD! This is when you see geese sleeping. Around ponds, they are loafing during the day. When they hit fields it is to feed!!! However, if it is COLD under 30 degrees or so , and there is some snow, then they fly to a feild and tuck in a sleeping pose to warm back up. Plus it melts the snow and the frozen ground so they can pick up corn, beans, etc....