Boy, a 3' dog can take up 6' feet without even stretching!! And they do claim the whole bed too by going sideways!
Hubby's dog used to holler to go out in the snow to pee at night. He would get up, open the door, walk across the porch to open that door and find the dog gone! Back in his bed, in the middle and growling when he tried to get back in it himself!! At was a game to the dog. It was worse if he actually went out, because he did the same thing, but with snowy feet and tummy. Nice cold wet bed then!
Buy an air mattress maybe? Those rocks are miserable!!
How long will this need to continue?