Really?! That's weird.
The lady that lived in this house before us had 12 dogs, and she had the same problem as you. She came home one day and found the bin men had slashed the bags spilling the poo all over the lane.
We haven't had a problem so far.
Where do you keep it in between trips to the tip, and how often do you need to make the trips?
And how many animals do you have that necessitate a tip drop off rather than having it taken with the rubbish?