Hokay, I just gotta help out a fellow animal lover if I can. First, let me say:
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pet supplies & stuff. Good stuff. There are other places, but I use these guys, so ... address was handy.
Some of these answers might have been easier if you had indicated the kind of climate you live in. Guessing, I'd ass-u-me it's a cold but not terribly cold climate, maybe zero on the worst days? How much snow? How bad does it drift? You don't want them trapped under snow where they'll suffocate. Yes, snow will suffocate, I don't care what anyone chimes in here with.
IFF it hardly ever freezes there and you never/seldom get snow, a nice box with some soft, fluffy rag-blankets, straw if you can get some, makes a nice bed. Insulation's good too but NOT fiberglass or anything like it. Plain styrofoam's not good either. Blueboard's better. They don't need anything else other than a place to get out of the wind and rain. With a nice place to curl up that's dry and not drafty, they'll be able to easily stay nice and cozy without help. But, if per my initial assumptions above: Please see inline:
Meaning you feed them? If so, you'll have to do it over the winter if you make them a place to sleep. Else they'll sleep near to where they eat most of the time. It's the feral way.
: Over the last year we actually can now touch and play with them but : they will not come in the house. They truly are wild.
Sounds like definitely third generation feral or more. You probably already know they can be real hamgurger machines if you do something they don't like and/or feel trapped .
: This winter I would like to build them a place where they can stay : which will keep them relatively warm.
All the stuff mentioned above goes here. Plus maybe a swinging door if you cant' be sure of keeping the wind from getting in, and especially if you can't keep the snow and ice rain out. Dampness and wind is much more harmful than temperature, as a rule.
: I can easily build them a small house and put a blanket in it but I : would like to insulate it and maybe add heat.
Insulation; great idea. NO FIBERGLASS!! Try the 1 1/2" thick blue-board stuff; comes in 2 x 8 foot pieces. Cuts like a dream, easy to shape. Consider a plexiglas window if you want them to stay inside where they can't keep track of what's outside easily. Ferals don't like feeling confined and not knowing where the 'enemy', perceived or real, is. They don't usually like corners either.
: Is there any electric heating pad type of thing that I can buy to use : inside this cat house.
Yup: Drs Foster & Smith has just the thing for you. Very little heat generated UNTIL they lay down on it and trap the heat in. Low wattage, waterproof, and generally safe. In fact, when you touch them you'd swear they're not working but if you keep your palm against it for a minute or so it soon becomes realy cozy feeling. Use a GFCI though, just in case they chew the cord. Tape the plug if you have to use an extension cord. If you don't have GFCI outlets, you can buy little plug-in ones for extension cord use. Got three of them msyelf. YOu would only need to add heat if you get -really- cold winters, and it gets under twenty degrees for long periods of time and colder . : I want it to be safe since it will be close to my house I don't want : to start a fire.
Foster & Smith heated pads are great - we use them for sick, injured kittens that we foster. We keep a couple layers of cheesecloth over them to soak up the pee, water & other spillage. Ferals will want it covered; besides, you don't want them chewing on it and ruining it.
: I was thinking about those electric pipe heaters that are used to : prevent freezing but not sure if they get warm enough. NO! NONONO! Wayyyy, too hot! Too dangerous too. You do not have to heat the house; their own body heat will do that as long as they have a nice cozy place to rest/sleep.
: Any suggestions, electric or otherwise?
Make the enclosure as draft proof as possible, but be careful not to make it air tight - they must have the fresh air to create the body heat they need. And to breath, of course . : : Thanks..
HTH,
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