Jim, I understand that each dog is unique (sp?), but we've used "training collars" on our fosters (dogs) and have had success with each one "controlling" thier behavior as far as how far they "wander" off the property.
Keep in mind, some collars also have a "beep" mode where you activate a "beep" sound instead of a shock. All of the dogs in a short time have learned that if we call and they don't come, we first "beep" them. At first of course they wouldn't come if we "beeped" them. Then them with a low setting "shock" and then work our way up to where we could see that the "shock" affected them and then they would come.
The dogs now know if they get a beep, if they don't come, a shock will follow.
Now, I will admit that the 85lb yellow lab needs the setting to be on maximum to get her attention.
We just feel that it's unfair for a "foster dog" to be on a leash all the time while our dogs roam free. After we see that they can handle a leash, we put a collar on them. Never had a problem or an adverse effect yet with any of them.
Nice thing to is that when we take them out at night, we can usually see where they are on the property by the flashing light that "blips" on the collar.