Dog wont Go on leash or backyard

Question
How do we get our dog to do her business when on her leash or free in the backyard? She's used to running wild, we just adopted her as a stray last week. But, she's been leash trained (only 18 mos. old says the vet), responds to commands and is well behaved.

I'm sending this a second time as when I hit the "check spelling tab" on the first one the page disappeared. But, if you should receive both, I apologize.

Answer
Because your dog is friendly to humans, she is not feral; this suggests she has been in a home with humans.  Her refusal to eliminate on leash or "free" (so long as you are watching) may be the result of someone else's inability to house train her and anger at the presence of urine or feces.  When a person reacts to urine or feces in the home with anger, and abuses the dog (with so called 'discipline') the dog HAS NO IDEA what's going on.  The dog DOES NOT associate its own urination or defecation with the anger and resultant "discipline", but it does learn to associate this abuse with THE PRESENCE of urine or stool.  The dog then does the most obvious thing: refuses to PRODUCE urine or stool IN FRONT OF its human cohabitant.  At this point, that would be you.

You must persist in your efforts.  put a very long training leash on the dog so she can get away from you at a comfortable distance, but not so far that you can't see what she's doing.  Do not give her ANY opportunity to eliminate indoors and you accomplish this by keeping the same training lead (15 feet)on her indoors when you are at home and observing her.  It appears (from the fact that she won't eliminate on leash OUTDOORS) that she won't eliminate indoors, either.  If she does begin to demonstrate elimination indoors (circling), interrupt by clapping your hands, then take her immediately outdoors and WAIT for as long as it takes until she eliminates.  Then heavily praise and reward with small food treat.  When you are not at home, confine her to an area (such as the kitchen) where her inappropriate elimination will not soil carpets, etc.  If you approach this with a calm demeanor, if you reward EVERY TIME she eliminates outdoors, and if you give her fair opportunity to do so (at first, every three hours until she gets the point, then at LEAST four times daily), she will choose to eliminate outdoors (for reward and praise.)  This may take a while as you must undo the damage done by someone else, but it will work (ultimately.)