My creatures cannot move body parts.

I think SL desperately needs a way to animate prims. llSetPos and llSetRot on child prims does not do very well. I get crashing when the object runs into things. Joints are far too limited to be useful. You should be able to link joints to child prims.

I know this has all been spoken before. Please help me. My dogs look like lifeless blocks of wood.

It can be done. You should check out Gurgon Grumby's cyberdog "Beta". All of its joints operate, albeit within the limitations of SL. But he has a lot of moving joints.