Why does my garage feel colder than the outside?

[Cobber]

We're expecting temps in the single digits here in Indiana for the next couple of days, so we're moving the girls into the garage temporarily. Right now it's about 28 outside, but 46 in the garage, but the garage seems colder to me. Now the garage does have a concrete floor, but we're housing the girls in a repurposed parrot flight cage about a foot off the floor. They'll be on cardboard with some shavings and 2x4s to roost on, with breathable fabric over the whole contraption. (pics incoming)

This winter business stresses me out!