I am sorry to hear that Esther is having difficulty passing firm, dry, very small or very large stools, I can give you some recommendations to help with that.
One is to increase fiber by adding canned pumpkin (not pie filling, just pumpkin) or plain cooked squash to each meal. One tablespoon to each meal for a small (Pug sized dog) to 2 tablespoons to start. These are just guidelines, you can adjust the amount based on her ease passing stool as well as whether her stool is too soft.
You can give her cubes of watermelon or cantaloupe for treats too. These fruits are high fiber and high in water content, won't hurt her and most dogs love them.Make sure to increase her fluid intake too, as dehydration can contribute to constipation.
You can add low salt chicken or beef broth to her food. The more fluids she takes in the better so if she likes to lick ice cubes give her those as well.
Slow walks can also sometimes help to get the intestinal tract moving properly too.
You might also wish to add a probiotic to get her gut bacteria back to normal. Fortiflora, Proviable, or Benebac are very good ones.
Please let me know if you have any further questions.