We do deep litter in both our raised coop and indoor pen; last winter I kept water in the indoor pen, set on a heated base. The idea was good, but I struggled with the messy water issue all winter long, mold-yuck. This winter I plan to put their heated base and large waterer outdoor in their run. Rarely do we have weather so bad that they cannot get out to drink. If we get into an ice storm or other awful weather, I'll move it back in temporarily. We keep a heated water bowl outdoors for our dog and that works all winter long, so should work for the hens as well. I do keep feed available to them in the indoor pen year round. ~G