HI, I would definately wait until her third season and as advised either use a black dog known to carry chocolate, which has NO yellow, going back in the pedigree, for at least 3 generations and preferably none in a 5 generation pedigree. Or a chocolate dog, with 2 chocolate parents and 2 out of the 4 grandparents being black (carrying chocolate). If you use a black carrying choc, you can then breed her chocolate daughter to a chocolate, hopefuly retaining good eye , coat and nose colour because you "have some black in there". I would use a black carrying chocolate, with no yellow in the past, about every other generation in a breeding plan.
I am probably going to set the cat among the pigeons here, but when I started in Westies, many years ago, when "political correctness" had never been heard of, I was advised by three top breeders and exhibitors who are also breed judges who give CC's and also judge internationally that a Westie bitch should be bred at her second season as long as she was "forward" and no less than 14 months old when in season. The reasoning behind this is at this age was that the bones, in particular the pelvic girdle, was still pliable and the bitch would whelp easily, and would whelp any subsequent litters more easily in the future, if she was bred young for the first litter. Of course after that first litter she would have a year or 18 months "off". Believing this to be OK, as I was a newcomer and these people were "at the top" I did as advised with 3 bitches over the following 18 months. They all whelped good sized litters easily, with no losses, without assistance, I just sat and watched. They barely lost condition, any that was lost was regained very quickly, and they did the pups very well. In the litters that those 3 bitches had (2 -4 litters each), none of them ever needed any help at whelping. Lately the breed clubs and the KC have intervened, for the greater good, and since , when I have mated bitches for the first time at around 2 years old I have had nothing but trouble - C sections, oxytocin, small litters and "misses". If they miss, after a break of 12 months then it really
can compromise their reproductive ability - to have no puppies for more than 2 years. I dont think it is a co-incidence that I have to have much more "interference" at whelping these days.
I know that these are Westies, and not Labs and agree that a lab should not be bred at the second season unless, she starts very late and has a second season at 20 months+, but in my experience, to wait with some smaller breeds is a mistake if you want a bitch who self whelps. In trying to solve one problem - abuse of bitches- the recommendations that are in fashion today are not IMHO in the interests of the bitches safety and well being at whelping So who is right, those that want to see a bitch fully mature before she whelps, and have perhaps have difficulties or to breed say one season earlier than commonly recommend, to give the bitch an easier time. Its not a matter of greed, or wanting to have more litters out of a bitch, but to make it easier and less traumatic for her. It is a very traumatic experience for both bitch and owner to take a distressed bitch to the vets in labour in the middle of the night, in the middle of winter, for jabs/ops that could maybe have been avoided. I know I am going to get some flack for this, but I would welcome any input from those that can stay civil about it. Just another thought, I wish posters wouldn't jump down on people who say they are going to breed, assuming that they haven't done hereditary testing, arranged for good homes and have the correct facilities, time, etc - when they have, but just haven't said so. We all had to start somewhere and many, many well known exhibitors/trainers, (including I am sure many of the regular posters on this site, in ALL breeds started with a mediocre bitch as a pet and then "got the bug", and went on to become pinnacles of the breed or discipline. I think we should be a little kinder in the first instance and not assume that everyone who wants to start breeding is going to ruin the bitch, ruin the breed and supply the pet shops etc.