Yes, a lot of crossing has probably occurred here for good reason since the gene pool of imported birds in the US isn't large. I personally don't cross mine because it's not my culture and in that sense I don't consider it my place. I keep several lines for genetic diversity. There's plenty there.
I raise mine as meat birds. How fast they grow really depends on the flock and how they've been selected. If they are selected for fast growth, as mine are, they can be burchered at 4 months for a dressed carcass about 3-4 lbs depending on sex. They don't grow like broilers but they are very respectable meat birds. They lay great, but mine are broody so often their laying cycles are off and on constantly throughout the year.
Miss Lavender, I was very worried you'd be offended by what I wrote so thank you so much for that reply. The breed really needs people who are willing to be learn beyond the limited info that tends to get repeated by breeders who are looking for the next popular exotic chicken breed. I love when I meet new people who are into them for what they are!
16-20 weeks sounds good for these dual purpose Hmong, just like other breeds. Respectable size as well in my opinion. Information on the net is sparse on these birds, so this information is great. It really sounds like the "almost" perfect homestead bird.