Introducing my new puppy

Question
I live in the country about a quarter mile from an outdoor trading center and I
come across a lot of strays in the area because of it. Typically, I'll take the
strays to the local Humane Society but yesterday I found a really cute male
boxer/german shepherd mix (I think) sleeping on my front porch and I just
had to keep him. I don't believe that he's any more than 4-5 months old and
I'm currently working on house-training him and plan on taking him to the
vet with my next paycheck. He gets along great with my cat and even plays a
bit with my ferret. My problem, however, is that my in laws live on the same
property as my wife and I (their house is no more than 150 yards away) and
they have an 11 month old, male, and not neutered Pitbull who is still
EXTREMELY hyper and fairly territorial. Right now the Pitbull is locked up in
their house because of a broken leg so taking my new family member outside
is no problem but I tried to introduce them this morning and got nothing but
vicious growls. I'm pretty nervous about this because once the Pit heals, he'll
be back to being an outside dog. What would be the best way to get these
two to get along outdoors? I wouldn't want the new puppy to be trapped
indoors because of the big scary dog outside.

Answer
It sounds like even if your puppy accepts the dominance of the other dog, it may not be good enough for the other dog.  What you really have is a tough, difficult people problem.  It is irresponsible for your inlaws to let an ill tempered Pit Bull run loose.  They are unlikely to change on my say so.  While I wouldn't hesitate to call animal control if one of my neighbors did that, it is different with your inlaws.  Note, ALL ill tempered dogs should be spay/neutered at once.  Just what we need, him impregnating any poorly cared for intact females in the neighborhood.

It really isn't responsible to let any dog run loose.  One solution to the problem would be to fence your yard.  If anybody complained about the Pit bull running up and down your fence barking its fool head off, it would be your inlaws' problem.

If you have much else in the way of neighbors, your inlaws may be forced to do something about the dog.  How did it break its leg?  I hate to say this, but if they are letting it run loose, that may take care of the problem before long.

This is a tough problem.  While I have canned answers to many problems, not all problems have good answers.