Are the giant breeds effecient meat producers?

I read somewhere the bone-to-meat ratio in some of them is not good for production.

Bone to meat ratio is not good in young fryers, they build bone before muscle.  Feed conversion ratio isn't as good in older animals, my guess is they burn more just moving around.

Flemish giant and other very big breeds grow skeleton first to support a larger maximum adult size. They don't fill out muscle (and ergo meat) until like a year or older. I had two Flemish does and sold them quick as I could. **They ate more than I was giving my two milk goats! ** And because they need to be most of their adult weight before breeding the first time, and they don't mature to be able to breed until later, I would have had to keep them nearly a year before even getting to breed them.

I have had good experience with two does that were 3/4 new Zealand and 1/4 Flemish giant. I have heard others say they have good producing does of that ratio of the cross. But you still get some pop up that are big and lanky throwback to the Flemish and just won't fillout in a timely manner which makes rabbit such good meat animals.

If you want efficiency find people actually breeding for meat and that cull for bad mothering etc. Show breeders may have that breed but they wont have the traits you want because they coddle them and keep show winners that are terrible moms or have litters of 3 and 4.

I always suggest to people New Zealand, Californian, florida white, or dutch. I have one mutt doe and I'd like to get a few going again I'd like to get a nice shaped dutch doe and a real nice new Zealand or Californian buck.