Hi,
As a breeder i have looked into this.You can have as many dogs on your property as you like as long as you dont' breed them,you are looking after them and they are not causing a nuisance.You are also allowed to keep up to 4 breeding bitches and as many dogs as you like.The amount of puppies the 4 bitches have make no difference at all,so in all if you stick to 4 breeding bitches you will be fine.
I have heard of cases where people have been prosecuted for having more than 4 bitches and the courts do seem to frown upon it for some reason even though they have no quarms letting more