Hi, and as our dear and respected friend Petrock said, welcome to the clan. They are beautiful as a mixed flock, but you should not let them breed as that. Just make a couple of pens, take one black cock and a few (2-3-4) of your nicest hens, and the same for the whites, let them live enclosed for a couple of weeks, and then start collecting the eggs and put them in the incubator or under a broody. They will then breed true, and you will be able to build up a flock. Read this book (the last 1/3rd of the book tells you about Langshans), it gives you a good introduction to the breed. It is best if you download the PDF to your computer, it loads much quicker every time you want to read. http://openlibrary.org/works/OL16513859W/The_Asiatics
When you have read that, you can also read this book, at the end of the bit about Langshans, i tells you how to create your own blues. You will find it a lot harder to keep a good lacing on them than with the Andalucians, but ask for advise, and you will get there. http://openlibrary.org/works/OL13541903W/Wright's_book_of_poultry
They are old books, but that makes no difference. Enjoy reading!
When you have read that, you can also read this book, at the end of the bit about Langshans, i tells you how to create your own blues. You will find it a lot harder to keep a good lacing on them than with the Andalucians, but ask for advise, and you will get there. http://openlibrary.org/works/OL13541903W/Wright's_book_of_poultry
They are old books, but that makes no difference. Enjoy reading!