I wouldn't be so sure. If you have a family tradition or a ruling from your rabbi allowing Cochin as kosher by all means follow this, but it was a huge controversy in the 19th century. In fact, this is likely the first chicken breed to have its kosher status questioned since the time of the...
If I would just raise chicks for meat soon as they are big enough does that count as chicken keeping? If I want a pet chicken that doesn't lay eggs (but not a rooster) are their good options?
The OU in united states allows wild ducks (mallard) but not with all black beak, others forbid it. It is discussed in many poskim for example see Kaf Hachaim (Yoreh Deah 82:23) and Tzemach Tzedek responsa # 29 https://judaism.stackexchange.com/questions/110548/is-there-a-list-of-kosher-duck-species