I remember a discussion on another thread (might have been one of Blosl's) about buying and shipping east to west or west to east or south to north or north to south. I could see how one bad experience could travel word of mouth and become ingrained. Is there any evidence to back up where we should buy? I have a hard enough time just finding one good breeder willing to ship my preferred breed. This is one of the reasons I put the Ohio Nationals on my bucket list.
changing the subject:
I am becoming a dual purpose guy and acknowledging that I am not truly productive in meat or eggs but trying to achieve a productive balance. I also am beginning to see that my goal "should be" to improve my breed of choice and not keep looking for the best dual purpose breed.
Don't limit your options based on location. Get the 'best" that you can, wherever you can. The only way shipping north to south, or south to north would make a difference if it was from Canada that had not gotten above 80, and then sent them to Columbia SC where it was 101 and 60% humidity. The initial drastic change to an extreme would be tough to tolerate. For any bird. You are not going to ship them in that kind of weather anyways. It would not make a difference the other way. Spring and fall are good times to ship. Mid winter, ship South. Mid summer, ship North. You get the idea.
The most likely problem would be a disease pressure on your poultry yard getting the newcomer sick, or vice versa. Then you were smart enough to quarantine the new birds for a few weeks to a month.
Improving your breed of choice is certainly your goal. There is no best. There is only a best possible for you. The only way you are going to improve them is to get to know them like the back of your hand. the big things and little thing. Know their type, and why they have the type that they do. Know it all.
Bob used to recommend printing an "ideal" picture and putting at the "poultry shed". I thought the emphasis on a constant reminder starting out was good advice, no matter how it was done. You want that image in your head, and the feel in your hands. You want to develop a sense of what they should feel like to.
A simple color like your Australorps allow you to focus on other than color first. In difficult colors, you can't just ignore it, even in the beginning. Some colors are hard to fix once they have went the wrong way for a time.
There is no way someone can intelligently breed anything without looking at the birds and saying what is wrong or right. Then handling them and realizing the same.