Welcome to YT! How old are your pups? My baby weighs a little less than that at 12 weeks and losing weight imo is not an option lol. What food did the breeder have them on? If they are really picky I would stick to what the breeder had them on(if you're trying to change it). You could always sprinkle some cheese or soak the kibble in broth to see if that will help(but this could also lead to eaters who will only eat kibble with the add ins or the puppies will eat the add ins and leave the kibble). Sometimes these puppies are just stubborn! If the add ins dont work you can always take the unused portion back to the store you bought it from and get a refund
. I would love to see pics of your pups!