I discovered that a really good thick wedge of old newspapers provides good insulation - and can simply be thrown away when they get too wet and grubby. I used to put food down for a stray at my old house in a covered tray (unused for specified purpose at that time!) as I didn't have a shed for him to get under cover. Never could catch him, poor thing must have been so badly treated: got to the point where I could get to arm's length, but he'd lash out if I reached my hand out for him to sniff, and used to stand there and swear at me while I was putting food down, etc. Had to stop feeding him when he started coming into the house during the day when I was at work and terrorising my 3 (at the time) - and peeing all over the furniture >.< - sorry stray puss, my 3 had to come first.