It is very important your cat colony has adequate shelter. A solid shelter will allow them to get away from the wind, rain and snow. Cats living under a shed, deck, stoop or in a window well are not adequately sheltered.
-Never use blankets, towels or similar items in a cat shelter because these items get wet and freeze. -----Straw is great as an insulator and wicks away moisture from the cat, keeping them warm and dry.
-Face the entrance of the cat shelter towards a wall so the wind doesn't blow in.
-If you use a heating pad make sure the heating pad only covers half of the shelter floor. The cats have to be able to get off the heating pad without leaving the shelter.
-We recommend a shelter with only one opening as a shelter with two opening will have the wind go right through it. All opening should be 6"-8" in diameter. This will prevent larger wildlife from getting inside.
There are many great options of outdoor cat shelters on-line.
Feral Villa (No skill required just a credit card and mailing address) is one of many options.