If it's like the UK, there are some racing greyhound trainers who rehome their own dogs once retired. More commonly they end up in rehoming centres like our boy or sometimes are left to a worse fate. The industry in the UK doesn't require that owners or trainers provide a meaningful amount of lifetime support for a dog once their 2-3 years of racing ends and are no longer economically viable.What's a breeder rescue?
Our local rescue proactively go out to racing kennels to get dogs and will never put a healthy dog down. Some of the best and most kind people you'll ever meet.