We have a Labrador who has always been small (but healthy!) since the day we brought her home 5 years ago
She's a "fox red" and only 19kilo at the moment (although her weight has been known to be 21/22kg any more than this and she is overweight says our vet)
I never released until long after we got her that there is an English Lab which is more stocky and an American Lab which is more athletic but she definitely fits into the latter. Although I had never know such a small Labrador!
Interested to hear the variations in size and also to see if anyone else has a small lab like ours