You know I just thought of something. If space marines ever got a birthday cake from a human or something there would be a lot of candles. I am trying to picture what a cake with thousands of candles for Bjorn now. Also as Gobmaw said You think with how big the bureaucracy the imperium has there are mistakes and someone would get the wrong gene seed some time. I do wonder how that would go. And what happens to a chapter when there is no way to rebuild it and they are reassigned to another chapter. It would take a while to get used to the survivors in the new chapter.
if i remember right then he died cause he wanted the other salas to take his gene seed he was sitting on a throne for like 1000 years and that made him unable to move
It was way longer than 1000. He was one of the original founding salamanders. His body was basically destroyed from age and he asked them to take it beacause he couldn't function properly anymore.
Chapters that have a home world (Ultramarines have Ultramar and the surounding planets, Imperial Fists have Inwit and terra, and possibly few more planets) Recruit from those planets. But crusading chapters like the Black Templars create small bases on planets they fight on that take in recruits (children between age 6 and 15 i belive) to train and hopefully make them in to astartes. That marine was WAY more than 1000 years old, Think he was 10,000+ year old and had been sitting in a command throne for almost that entire time. His body was so fragile and malnourished that he could not move, or do much of anything at all.
To the OP, No they don't choose. They get chosen. As others have said, most Chapters have at least one world they regularly recruit from. Usually the Chapter is even based on or near their prime recruiting world. Other Chapters recruit from a range of worlds, recruiting in turn from them. Most of these are for Space Borne Chapters like the Dark Angels and Imperial Fists, Though the Ultramarines have a similar recruiting policy from the worlds of Ultramar. But there are Chapters that recruit from the nearest worlds to them at that time. Usually this is because they need the recruits but don't have the luxury of picking up new recruits from their usual recruiting grounds and then its usually on a world they've fought on or near. I suspect that this is how the Black Templars recruit. There are those that have lost the rights to their recruiting worlds and have been sent on a penitence crusade, the Lamenters Chapter and The Scythes Of The Emperor are good examples of these. They too must recruit from where ever they can.