Welcome to you and Lexi. It's awfully hard on a puppy to change its food suddenly. If you don't want to feed what the vet recommends, you might try softening the breeder's dry food with water.
You might also try a very bland diet for a couple of days, then phase in the soft food. Poach a chicken breast in water only until it shreds easily. Take the chicken out and shred it -- put it in the fridge for a little later. Let the broth cool in the fridge, and skim the fat off the top -- too much fat could cause digestive problems.
Then cook a little rice in some of the chicken broth (I use 1 part rice to 3 parts broth) until it's really soft.
For the first feeding, just give the rice. At each additional meal, add a very small amount of chicken until you're feeding about half rice, half chicken. Then you can start to phase prepared dog food back in by adding a little more of it to each meal.
But really, you should talk with your vet first -- based on his examination of the puppy and his knowledge of her age and condition, (if he is a GOOD vet) he will be most qualified to partner with you to help your dog live a long and health life. I've taken info found here to my vet and he has always been willing to sit down with me and explain why he recommends for or against an idea. |