The average adult dog needs about 70 × weight(kg)^0.75 kcal as their RER, multiplied by 1.2-3.0 based on activity level. A moderately active 10kg dog typically needs 400-500 kcal/day.
Yes. Growing puppies need 2-3x the calories of adult dogs. Puppies under 4 months may need RER×3, while 4-12 month puppies need about RER×2.
You should be able to feel your dog's ribs easily but not see them. If you can't feel ribs at all, your dog may be overweight. Overweight dogs should reduce calorie intake by 20-30%.