The main problem is that they have a pretty low reproductive rate. Gpigs tend to have a VERY long gestation rate, 70 days, and only have on average 3-4 babies, unlike rabbits at 30 days and up to 14 kits.
You'd be looking at about 4-5 months to get to a 2 pound animal, and dressed out, an adult animal (32-36 oz) would probably yield roughly a pound of meat. The skull would be the largest and heaviest portion, weighing about a third to half a pound, but if you're doing a whole foods thing, the larger dogs (not sure about what breed you raise) would PROBABLY be able to handle the large skulls, if you feed rabbits now, but... the skull is a pretty major part of the animal.
As far as to the one pound growth rate, you're looking to achieve this at about 8-10 weeks of age, but again, that's NOT dressed out, that's full animal. Babies (up to about 5 weeks) honk through the food, and you will find that they start eating solids at about 4-5 days of age, some will start nibbling on pellets at about.. 2-3 days of age. They're born fully furred and ready to go, and VERY cute I might add, until they get to that 12 week intermediate 'teenager' stage.. lol Babies do tend to go through a LOT of feed. I typically go through about ... maybe 150 pounds or slightly more per week? Cavy feed is much more costly on average (generally about 2x more) than rabbit feed is, due to their need for ascorbic acid, and also because most commercial rabbit feeds have antibiotics in them, you cannot use them for cavies for two reasons: 1. Cavies need about 30 mgs/kg of Vit C per day, and it breaks down in 90 days so the stuff HAS to be fresh. 2. The antibiotics used in rabbit feed to prevent the spread of coccidiosis is rather harsh and somewhat toxic for cavies. Hence, you're doubling your feed bill for half the output...
Make sense?
Hope this helps!
Kirstin