http://www.kuranda.com/main/index.asp

Go to products...then to the poly resin...we've used them in the boarding kennels I worked at, and they held up remarkedly well.

For a GSD they recommend 40x25 I think.

Not sure about the other dogs, maybe someone else could answer that one-came back to edit, I would try it very supervised at first-leave them out there and keep an eye out through a window..if any problems, than no, but if everything looks good I think it should be okay as long as Travis isn't particularly toy/food/space aggressive. Some dogs don't like others invading their personal space too much.