MMWB
Overrun with beasties
If the best production in in mind, stick with the commercial. I am sure you can keep them as healthy with more natural methods, but it will take some research and real effort. Commercial feeds tend to have a lot of trace elements in them that could easily be missed with a more 'random' feeding of natural mixed feeds. That is why you want to really know what rabbits need. I'd recommend veterinary journals or go to a university library and find some thesis's or doctoral dissertations relative to rabbit nutrition. Google might not cover the trace stuff. I expect most commercial feeds have things like copper and selenium added that may not be naturally abundant in some areas, but add a level of disease resistance that rabbits without don't have. In my area, we have plenty of selenium, but copper is low. That is why I copper bolus my goats three times a year. Give that same copper to sheep and you will see liver failure. All of that being said, for as long as you are raising butcher rabbits (the ones to butcher, not the breeding stock), a small deficiency in some elements may not make a difference. In your shoes, I'd consider running a study. Feed half of a litter (randomly chosen) based on commercial and half on my 'home brew' and track not only weight gains, but general appearance, energy and health (as objectively as you can) and then over a year of litters, you'll know the difference. If you did such a study you would do the study independently for breeding stock (to also note effects on conception, delivery and viability of the kits) vs butcher/sale stock and you would not do them at the same time. If you already have good records on the breeding stock, you wouldn't need two groups to see the effects from change in feeding. Just compare before and after. Seasonal effects will be a variable too. Lower protein in the summer may not be as significant as the winter. Sorry, I tend to get long winded...