The first question might be to ask whether the pigs were eating the clover. They clearly were, and lots of it. The were mowing through a paddock in a few days in the last month. I opened up the gut of one of the pigs at slaughter and took the picture below. Full of clover.
Another question is to wonder if I'm feeding too much or too little feed ration. My first year, I fed free choice and the pigs were too fatty for the average home cook's tastes. I chose 5 lbs as the ration last year and continued it this year essentially at random. The quality of the pigs and that fat/meat ratio was really good both this year and last year, so I'm hesitant to change it up.
There are lots of other questions, such as "is the benefit of the clover somewhat minimized by the increased exercise they get in foraging (I have a hard time believing that )", "Did improving the pasture not actually make that much of a significant improvement in the nutrition the pigs were getting from it (in other words, perhaps the pigs ate and converted just as much energy from last year's pasture), "Is there a specific age in which they start to convert pasture better because their gut has developed, and should I keep them longer to take advantage of this," "will continued selection for the best animals improve the feed conversion over time?" Some of these questions will be difficult to answer without rigorous controlled studies--studies I would like to do, but need to have sufficient herd numbers to be able to replicate my treatments (I am a scientist after all).
In the end, even though I didn't get the full benefit of the clover planting that I had hoped, I'm still pleased with how it turned out. My pasture is much improved from last year, and it should stay that way for several years with minimal management (white and ladino clovers tend to reseed and stick around, as compared to red clover). The pigs clearly ate a lot of clover, and I suspect the same nutritional benefits that come from eating grass fed beef are present in the meat of these pigs. I would really like to do a full nutritional comparison to supermarket pork--especially to look at things like omega3s.
One thing that I now have a much better handle on it the actual feed cost of raising pigs in my system. This year, it is about $170/pig. Hopefully, I'll find ways to nudge that down little by little over the upcoming years.