Because it is 15 degrees with a 40 MPH wind and I would freeze to death.
They run and follow me all day but at bedtime they become bellybuttons.
Today's low was -27°F at 7:00 AM. The high today so far was -5°F around 1:20 PM. There wasn't any wind all day until about an hour ago. After dark it had gotten down to -12°F and with the wind the temp is back up to -5°F. Our high for the day is going to be at midnight tonight and it looks like it will finally get above zero. If I remember correctly the weather forecast is calling for above freezing temperatures Saturday.
All the birds spent the day in the coop although it was a sunny day. The turkeys are outside on their roosts again tonight.