Pets had babies and they want to keep one...

[Anthony Harmon]

I moved tenets into my property over a year ago. When they first got in they told us they wanted pets. I agreed to them having two pets(two small dogs under 10 pounds) well they purchased a boy and a girl from a breeder. Those dogs made it happen and out come two little puppies. ;) yay... They now want to be able to keep one of the puppies and sell the other. I am ok with doing another pet fee and having them sign a new addendum for the third dog. (In the first year the two dogs have done next to no damage that I am aware of) My question is am I able to write into the addendum that I need proof the first two dogs were neutered? Is that a legal/moral thing to ask them to do? I want to ensure this does not turn into a puppy mill... Any and all help would be great. Anthony