RE: squirrel urine
don't know about urine but the best way I have found to train is to use the skins of the squirrels.tie the skin to a line on a long pole(fishing pole works). drag it from tree to tree,then tie it just high enough up the tree the dog can't reach it.drag a dead squirrel from tree to tree so the dog will have a real squirrel to catch,will help a bunch.
that works for deer also(that is to drag)not tie up a tree.
I am not a hunter I am a whitetail population reduction specialest
remember keep your back to the sun, your knife sharp, and your powder dry.