Out of curiosity, realizing different lines mature at different rates, what does the "average" lab shown for conformation weigh and how tall is it at six months? Dogs? Bitches? Will be interesting to see the range of answers. No agenda, just a hmmm, I wonder Sunday afternoon question while listening to my husband snoring the couch (TV on of course).

Gee...the snoring husband on the couch sounds so familiar....TV on too. Are you writing from my house?? As for the dogs...I'm not a breeder but I do have a handsome young 9 month old yellow boy entered in his first show. He is about 21" tall and 78 lbs. moderate build and as fresh as can be!

I have an almost 6 mo male, he is 55 pounds an about 20 inches tall.

Mine's almost 6 months(5 1/2 actually) and he's 64# and 21 1/4 inches, he's almost as tall as momma and she's 21 1/2. He's also the most mellow boy we've had besides Codey.
His sisters are a little over 10# less and not quite an 1 inch shorter.
They're looking all growed up already, Sniff :'( !!!

How about girls? 6, 9 & 12 months. I agree, different lines grow at different rates also but what age do you find your girls hit full height growth? TIA.

I've read that a puppy is about 75% of its adult size at 6 months. Not sure if this means height or weight. Also not sure if that is a broad generalization across breeds. Small breeds mature faster than larger breeds.

With the info on my girls that I could find, at 6 months, they were all between 17-19 inches and weighed between 50 - 55 lbs.
At 2 years, same girls ranged between 77- 88 lbs and 21-22.5 inches at the withers.

What about boys?

Think bigger

Is there any size at six months (small) that would predict they won't meet the standard as an adult? Or, is it too unpredictable because they mature at different rates. In short (no pun intended), if a pup you are running on otherwise looks promising, are there circumstances where you would place them as pets at six months based on size?

I would look at the adult size of the parents, grandparents, rather than size at six months.