If it's not the food (test by trying a fresh
small bag of exactly the same food) then I strongly suspect it's the maturation process.
Below is a copy of a post I've often made when this comes up.
IF the food is fresh and the age is 10 months or less, I suspect it's a streak of emerging "self-regulation." Below are exceprts that I've posted before to others who've reported the same thing:
I understand your worry, because I went through that with my Puff, although with her it was at about 8-9 months of age. However, there are such remarkable variations in the rates of development of Labs, it is almost certainly a similar thing.
Not to worry -- instead, REJOICE !!
It was through this that I discovered my Puff is largely a self-regulator of her food intake. That puts her in the minority; most Labs are gluttons and some could easily kill or injure themselves by over-eating if given a chance. Self-regulating (according to a poll I conducted on JL several years ago, responded to by about 70 owners) is only found in about 10% of Labs. And, at that, it applies only to regular kibble and not to steak, fish, cat food, horse manure, etc.
Puff had gone from eating about a cup of food a day when she was 6 lbs at 9 weeks age to eating 5 cups/day (divided into 2 meals) at 8-9 months. Then she stopped eating for a couple days and when she did eat, she ate only part of her food.
I looked up puppy nutrition in several dog vet books, The UC-Davis "Book of Dogs" says, for instance, that when puppies are very young they need to eat about 2X the amount of food that an
adult dog of that same weight would need.
BUT, as they approach maturity, that
need multiplier decreases from
2X down to
1X -- with 1X meaning they need the same amount an adult dog of that weight should eat.
I measured the amount Puff did eat when she resumed eating and made available only that amount for 15 minute periods.
She ate that amount. That lasted a bit and then she stopped eating again. I decreased the amount again.
Puff finally went from 5 cups/day down to her current 2 cups/day (divided into 2 meals; but supper has green beans added to that amount of kibble).
I suggest you count yourself lucky and begin decreasing the amounts you feed until you reach a stable balance.
And another:
The first time it happened with Puff, she pretty much ignored food (except a few nibbles on irresistible treats)
for a couple days.
It was then that I began really reading and absorbing what the vet books said. My first Lab, Bess, never met anything edible she didn't want to eat (except raw onions and raw mushrooms), so I was as unprepared for a Lab refusing to eat as I would be if seeing her fly.
But -- if it'll be any comfort to you -- in nature, feral dogs and wild canids often go for a couple days (but not always by choice) without eating food and then stock up when fortune favors them with scavenging a carcass.
Suggestions:
1. measure and reduce by 1/4 the amount of food you've usually fed at a meal;
2. measure anything left so you can
deduct that amount from the next meals offered;
3. continue to feed the reduced amount until ______ again skips some meals;
4. repeat steps 1, 2, & 3 as it becomes needed (it may happen several more times);
5. IF you do notice unusual behavior (listlessness, generalized apathy, loss of activity and interest, etc.) DO take ____ to see your vet.