None of those are "meaties" per se. They are all dual purpose birds, which could be raised for meat or eggs. The cockerels would be processed around 14 weeks old instead of 7-8 weeks like a Cornish-Rock cross. Since they are dual purpose, they will be more meaty than a RSL or Leghorn. They may not weigh as much at 14 weeks as a Cornish X would at 8 weeks. They also benefit from caponizing, IME."Our Fry Pan Bargain is an economical way to raise delicious, fryer-sized chickens for yourself and your customers while enjoying a more active bird. This all- rooster assortment may include one or more of the following breeds: Golden Buff, Rhode Island Red, Black Star, Black Jersey Giant, Salmon Faverolles, Speckled Sussex, Cuckoo Maran, Welsummer, Black Australorp, Barred Plymouth Rock, White Plymouth Rock, Buff Orpington, Silver Laced Wyandotte, Buckeye, Golden Laced Wyandotte, and Dominique. These roosters take longer to reach butchering size and won't be as large as the broilers, but good things come to those who wait. No guarantee on the number of any type on the assortment. Roosters only."
these breeds are not really meaties though are they? some grow slow not?
In my experience, they are not as tender and I would not, for example, make fried chicken with them. But they make great braised dishes and wonderful chicken broth. They will be more strongly flavored than a Cornish X, too. Yummy, but not as tender as my family likes for eating "plain chicken."