Butchering age really depends on the breed, the genetic line, and to some extent how and what you're feeding. It also depends on whether your goal is fryers, roasters, stewers and/or prime pelts. All rabbits of all ages and sizes are made of meat
, it's just that most people want the most meat in the shortest time (or at least at a minimum investment of feed costs).
One resource for guidance is the American Rabbit Breeders Association standard on meat rabbits:
- Meat pens and single fryers have a maximum age of 10 weeks, and are expected to be 3.5 - 5.5 lbs each (at this age, pelts are still unfinished and if you keep them the best you can hope for is usually fur for trim, etc.)
- Roasters are under 6 months, minimum weight 5.5 lbs and maximum weight 9 lbs (this is the age at which you are most likely to be able to harvest prime pelts, as well)
- Stewers are 6 months and over, minimum weight is over 8 lbs
I have found that the meat is fine and tender up to about a year (after that the meat goes in a pressure cooker). After about 12-16 weeks, rabbits get a little more attached to their pelt and are a little harder to skin, but then it's worth it to wait till they're in prime coat (mine prime between about 3.5 -5 months)
For commercial Californians and New Zealands, harvest is generally at 8 weeks. Commercial rabbits are intensively bred for high birth weights and growth rates, and it can be challenging to replicate that in private herds, but it certainly can be done with close attention to breeding animals that produce kits with those characteristics (or working toward it.
Satins are known to be slower-growing but more feed efficient than the commercial breeds. I have found this to be true, as my Satins used to take 12 weeks to reach butcher weight (I harvest fryers and use 4-5 lbs as my standard) but in 12 weeks the Satins still ate less pellets than my Cals and NZs did in 8 weeks.
I have been working for several years on improving growth rates in the Satins and now usually harvest at 9 weeks, with some bunnies hitting fryer weight earlier than that. (I may have lost the super feed-efficiency in the process, but I have not looked into that yet.) From the charts below, you can see that in the two breeds I raise, growth rate continues more or less steady until 16 weeks or so. However as
@Preitler mentions, rabbits can theoretically breed by 12 weeks, so most of us butcher by that age instead of separating all growouts into their own cages.
Here is an example of the growth rates I see in my Satins. This is one of this year's meat pen bunnies; you can see that he hit the minimum 3.5lbs just before 7 wks, and was at maximum fryer weight of 5.5lbs at 10 wks:
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For comparison and to show how growth rate changes by age in rabbits raised past fryer age/weight, here are two Champagne D'Argent charts. The first, a buck named Killian, hit minimum weight before 8 weeks and was at max at 10 weeks. Killian had a fabulous growth rate and is my current herd sire. (He actually had to be shown as a Senior while he was still technically a junior because of his weight.) You can also see the diminishing growth rate at about 16 weeks.
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Here is a chart from Realta, a Champagne doe with a less impressive growth rate, making fryer weight between 10 and 12 weeks. She actually continued on her growth curve until 22 weeks. The slowdown between 12 and 13 weeks was due to a move from the growing cage to a single pen; most changes tend to result in a very temporary slowdown or even slight weight loss, so keeping your growouts in a steady situation until harvest is a good idea.
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I have also found that butcher weight is not the only metric to use when deciding to harvest. You will probably find differences in the dressout percentages (meat-to-bone and -fat ratio) among your bunnies. Weighing your dressouts after boning is a good idea, so you can choose breeders that produce the most efficient meat bunnies.
Feeding practices also change both growth rate and meat percentage. In the summer months I often put my meat growouts into a tractor that I move around the yard. The bunnies in the tractor eat greens and free choice pellets, and they end up eating about half the amount of pellets than the bunnies in wire cages eating free-choice pellets alone. In the end, the tractor bunnies weigh less than the caged pellet-only bunnies, but at harvest I see that the tractor bunnies have quite a lot less fat than the pellet bunnies. Ultimately, I get about the same amount of meat for about half the amount of pellets when I can tractor them. I can't do this for more than a few months since once it starts raining it is difficult to keep the tractored bunnies from developing coccidiosis, but it's great while the season lasts!