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 window well are not adequately sheltered. Never use blankets, towels or similar items in a cat shelter because these items get wet and freeze. Always use plenty of straw. Straw is great as an insulator and wicks away moisture from the cat, keeping them warm and dry.
The first 2 links are cat shelters that you will have to build. The last link is a shelter you can purchase from Feral Villa.
Alley Cat Allies Feral Cat Shelter (More skill required)
Spay and Stay of Lake County Feral Cat Shelter (Less skill required)
Feral Villa (No skill required just a credit card and mailing address)
There may be other cat shelters that you can purchase or construct on the web or in stores. These sites listed are not a recommendation, merely a "help" list. If you have a listing you believe will help or any recommendations, please contact us.