Labrador playing with 2 shih tzus

Question
Hi.  I very recently (less than a week) received a labrador (american type) from a friend.  The lab is male, intact, 3 months.  He came from a breeder who breeds large dogs (labrador, GSD, pitbull terrier) and was responsibly cared for.

Before the lab arrived, I already have 2 shih tzus (both intact, male and female and 4 months).

The labrador would like to play with both dogs.  The female shih tzu likes playing with other dogs, including rough play, but the male shih tzu is much more reserved when playing with other dogs.

I think because the lab grew up with large breeds, he is not yet experienced with playing with much smaller dogs but he is quickly learning to tone down his play (sometimes, the lab would let the female lab be on top when they're playing).

I am anxious about the labrador and the shih tzus being left alone at home (I work and I leave them 6 to 8 hours during workdays).  I don't want any dog to get hurt.  I am especially anxious about the lab and the male shih tzu.  The male shih tzu generally doesn't want to play with the lab and he barks in a high pitched tone (almost like a shriek) if the labrador wants to play.

(I am trying to walk the lab at night to burn his excess energy but he still needs to get accustomed to being outside).

Will my dogs be safe being left alone at home?

Answer
It is hard to give a definite answer since dogs vary so much.  8 hours is a long time to leave dogs by themselves.  You may want to crate them.  It is only natural that a puppy resists its crate at first. What the puppy wants more than anything else is to be others, you, anyone else in the household, and any other pets. In our modern society, even if we are home, other things distract us from the attention an uncrated puppy must have. The only real solution is to crate the dog when you can't give it tha attention it needs. The dog may be happier in its den than loose in the house. It relaxes, it feels safe in its den. It rests, the body slows down reducing the need for water and relieving its self. Dogs that have been crated all along do very well. Many of them will rest in their crates even when the door is open. Skip the bedding. At first it gets wet, and later it can be chewed into choking hazards. A wire rack in the bottom will help keep the puppy up out of accidents at first. They are available with the crates, but a piece of closely spaced wire closet shelving from a home supply place is cheaper. I think the plastic ones give the dog more of a safe, enclosed den feeling. Metal ones can be put in a corner or covered with something the dog can't pull in and chew. Select a crate just big enough for the full grown dog to stretch out in. At first, you may need to block off most of it.

You may want to look into having a neighbor or professional dog walker give them a break mid day.