Why does my Collie not sleep in the same kennel as my dobies?

Has the collie grown a winter coat? If so he shouldn't feel too cold being in the garage and then in the kennel in the garage, but no harm in insulating the kennel itself, vet bed (if you haven't it already) is brilliant for keeping them warm. My collie loves her bed and absoultely loves when there's a fresh blanket put in, atm I'm using vet bed and also fleece blankets (they both wash well and dry quickly once you've gotten rid of the excess hairs on it).

Before we built on we had an old enclosed porch which was made of brick but not insulated or plastered etc. so I used a heat lamp one winter and the two dogs loved it, although it can be pricey on elec. I am too wary to use it where they are now as it's a timber shed (paranoid about fire hazzards) but if yours is a concrete garage might be worth getting a low wattage heat lamp (if there's such thing).

My collie usually grows her winter coat and by this time of year her fur is so thick I have to loosen her collar but this year although she's grown thicker hair around her shoulders and neck her coat is no way as thick as it usually is, not sure why perhaps the weather has something to do with it but she's actually moulting in places atm as if it's Spring. Very strange.

Of all the bedding I've tried from shredded paper, duvets, pillows, wool blankets, fleeces etc. and the bedding that works the best and you can wash and reuse is the fleece blankets and vet bed the vet bed is so soft and cosy so if you haven't it already perhaps try that for the collie.
Pity the 3 don't snuggle up together but I have found it can also depend on their mood, and obviously pecking order. My two sometimes snuggle up together and sometimes prefer to sleep in their seperate beds, I try to sneak up on them to see but once they hear me approaching they jump out and run outside.

There's also the snuggle safe heat pad but it can get cool during the night, I find them handy to have though.