Hi Jean
I'm so sorry to hear about your Pyranees.....you're right, how can they miss a dog that size, and why didn't they have the guts to stop and let you know!!! How tragic for you. I know how you are feeling to lose a member of your family.
I can tell you about invisible fence because we have our property fenced with it. First of all, let me say that there are many different types of "invisible fence." We have "CANINE CONTROL" and it is a franchise, so you can find them anywhere. If you can't get the dealer near you, let me know and I will find one for you from our dealer.
We have had our guys on the fence for about 11 years. I couldn't say enough good things about it. We have never had a dog cross the fence line to the road or out the back. I truly don't know what I did before it---just took stupid chances, I guess.
The service is wonderful. We had our fence hit by lightning a few years ago on a Sunday and they were there Monday morning to fix it. Right now we have about 7 people on our street with invisible fence---they all say the same thing, it's wonderful.
Please allow them to train your dogs and remember, they have to get a shock to know that they can't pass that boundary....I will tell you this, one shock is all it takes, at least with springers. They can be running a deer or a rabbit or a squirrel and will stop dead if they hear the audible sound prior to the shock. Absolutely well worth every cent!!! At first they will put the fence in and then set up flags around the perimeter of your property. I would say that it takes about 3 days to fully train your dog on the system. I don't take flags out as fast as they say, but I will remove every other one after a week or so, and then gradually decrease the amount of flags within a month.
Hope that helped you a bit. If you have any other questions, I'd be happy to answer them.
Evelyn