In my experience, litter size does tend to run in genetic lines, but not always due to the buck. Although it certainly could be your buck if all three does are having the same problem, I've never culled a buck for litter size issues. In my experience, my bucks' production varies from doe to doe. I guess if I was having this problem but I liked the does otherwise, I might try to "borrow" a buck and see if the does perform differently, before I started over from scratch.
How closely related are your does? And what age? I expect smaller litter sizes once does reach 3 or 4 years old, especially if they've been in production the whole time. I do see strong tendencies to have larger or smaller litters in the different matrilineal lines in my barn. And while production drops over a doe's lifetime, another thing I've noticed is that does from the big litter line (14-16 kits per litter during their first year in production) tend to age out faster. Most of them are down to 3-4 kits per litter by the time they are three, whereas does from the more typical litter size lines (7-9 per litter) sometimes still have close to the same number at 3 to 4 years old.
However, litter size can also be related to diet, which can be tricky to determine since most of us don't get to see what's going into the pellets or how they're stored. The rabbits in my barn are just recovering from a horrible year of production; I belatedly discovered they were suffering from not only a vitamin E deficiency but also some as-yet-undetermined issue(s) with the pellets. These pellets were no corn, no soy, organic, looked and smelled great, rabbits liked them... But I can't really name a problem I have
not seen in the last 12 months, which coincides exactly with my shift to this brand. Much of the trouble was reproductive: missed conceptions, false pregnancies, litters of 2-4, giant stillbirths, at least one or up to the entire litter being stillborn. All of these issues have tapered off quickly since I switched back to Nutrena. What I had been using for the last year was being brought up by a local feed store from a mill in the Lower 48, I do not know which mill. I might have blamed the rabbits (actually I did butcher a few of them
), but I have had some of these rabbit lines for many generations and knew what I
should be seeing from them.
This is the second time I've been through "pellet problems." The first time was with a locally milled brand that served me well for about six years until I started having failures similar to what I've had in the past year. That one was simply vitamin E deficiency, solved by supplementation before I could switch feeds. My point is that a brand that has been great can go wrong without warning, due to changes in ingredient quality and/or sourcing, processing, formulation, storage or transport, among many other possibilities.
Do you have any way to find out the history of your does, or the typical performance of the lines they came from?
Incidentally, the rabbits I did butcher for poor reproduction all had problems with their reproductive tracts, including mummified pregnancies, empty gestational sacs filled with fluid rather than embryos, and tumorous masses in their ovaries, fallopian tubes and/or bladder. The one buck we butchered had numerous lipomas and tremendous vascularization within the tissue of his belly skin. I have never seen any of these issues in my rabbits in nearly two decades of working with these lines. So if you do start over, definitely investigate what might be going on internally!
In fact that's why I prefer to linbreed almost exclusively: over time, I weed out the bad stuff, and know what to expect in the litters, so I generally know exactly who the problem is coming from when I see negative results.
