Puppy feeding and growth
How much should I feed a rescue puppy of unknown age?
Last updated 23 September 2026 · How we write and check this
Short answer
Without a confirmed age, a vet can estimate a rescue puppy's age fairly closely from its teeth and general development, which then lets you use a standard feeding chart for that estimated age and current weight, adjusted based on body condition since rescue puppies sometimes arrive underweight.
Getting a working age estimate first
A vet examining teeth eruption and general body proportions can usually narrow down a rescue puppy's age to within a few weeks, which is accurate enough to select an appropriate feeding schedule and amount, far better than guessing purely from size, which can be misleading for an underfed or small breed puppy.
Feeding a puppy that may have been underfed
If a rescue puppy arrives visibly thin, reintroduce food gradually over several days rather than offering unlimited amounts immediately, since a sudden large amount of food after a period of poor nutrition can cause digestive upset in a puppy whose system has adjusted to less.
Adjusting as the true picture emerges
Weigh weekly and watch how the puppy responds to the estimated age based feeding plan; a puppy that gains unusually fast might be younger and smaller for its estimated age than assumed, while very slow gain might suggest an underlying health issue worth investigating alongside the vet.
Key takeaways
- A vet can estimate a rescue puppy's age from teeth and development closely enough to guide feeding.
- Reintroduce food gradually for a visibly underfed rescue puppy rather than offering unlimited amounts at once.
- Weekly weigh ins help refine the feeding plan as the puppy's true growth pattern becomes clear.
- Unusually fast or slow gain compared with the estimate is worth discussing with the vet.