Not recommended under 8 weeks old. Between 8–12 weeks, very small crumbles are acceptable as training aids, but the amounts should be minimal. The concern is not toxicity — it is caloric displacement, digestive immaturity, and the high fat content. After 12 weeks, small amounts are generally appropriate with the usual precautions about portion size.
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What the age thresholds actually mean
Eight weeks is the standard minimum age for puppy adoption in most states, and it is also the point at which the GI system has developed enough to handle solid food beyond mother's milk. A puppy under 8 weeks should be on mother's milk or a veterinary milk replacer — no solid treats of any kind.
From 8–12 weeks, puppies are in the imprinting and socialization window. This is when treat-based training can start, which is also when many new owners want to begin using high-value rewards. Stewart liver is an appropriate treat at this age in tiny amounts — but "tiny" means literally crumb-sized, not a whole piece or even a half-piece.
After 12 weeks, small broken pieces are appropriate. By 16 weeks, puppies on a good puppy diet can handle liver treats at the same proportional amount as adults (10% of daily calories) without issue.
Why young puppies need special consideration
Three factors matter here. First, digestive immaturity: a young puppy's gut has fewer digestive enzymes than an adult, processes fat less efficiently, and has a microbiome that is still establishing itself. Rich, fatty treats can cause loose stools more easily than in adults.
Second, caloric displacement: puppies need a lot of calories relative to their weight for growth, but those calories need to come from a complete and balanced puppy diet. If 15% of a puppy's daily caloric intake is liver, that is 15% of nutrients not coming from the complete diet. This matters more in puppies than adults because they have narrower nutrient margins.
Third, vitamin A accumulation: liver of any species is very high in vitamin A. For an adult dog getting a few pieces per day, this is not a concern. For a growing puppy already eating puppy food (which is formulated with higher vitamin A than adult food), additional liver adds to the total load. Occasional treats are fine; liver as a daily food supplement in quantity is not.
How to use them safely from 8–12 weeks
Use the crumble at the bottom of the bag, or crumble a piece between your fingers until you have powder. A training portion for a puppy in this age range is a small pinch — roughly the size of a pea in crumble form — not a solid piece. The smell is strong enough to motivate at this size; you do not need a large piece to get the puppy's attention.
During an 8-week-old's training session, ten repetitions with ten pinch-sized crumbles is appropriate. A training session longer than 3–5 minutes is too long for this age anyway — their attention span runs out faster than their stomach does.
Portion guidance by puppy weight
| Puppy age | Portion per training session | Sessions per day |
|---|---|---|
| 8–10 weeks | 5–8 pinch-sized crumbles (under 0.5g total) | 1–2 |
| 10–12 weeks | 8–12 crumbles or 1–2 very small broken pieces | 2–3 |
| 12–16 weeks | Up to 5 small pieces, broken into halves | 2–3 |
| 16 weeks+ | Standard portion based on body weight (10% of daily calories) | As needed |
Signs your puppy is ready for treat-based training
A puppy is ready for treat-based training when it is reliably eating solid food, showing curiosity about what you are doing with your hands, and responding to your voice and movement. Most puppies hit this point around 8–9 weeks. If a puppy is still uninterested in solid food or has ongoing loose stools, delay treat training and address the underlying issue first with your vet.