Just some update shots. These boys are nearly 15 weeks old. They're possibly a little on the small side, but this could also be a matter of their living next door to the hefty meat hybrids (which would make turkeys look small). The only other concern I have about them is the slight pallor (almost a yellowing) of the combs. You can see it toward the rear of each comb. Their feathers are beautifully glossy and both birds are active, friendly and have terrific appetites.
Thinking about the yellowish combs, one concern is whether the lupins have higher than expected levels of toxins. Australian sweet lupins are supposedly low in anti-nutritional compounds, and can be fed raw, but apparently lupins from WA are almost always infected with a mould that (via its toxins) causes liver disease. (See www.agric.wa.gov.au/OBJTWR/imported.../lupins/Lupinbulletinch13.pdf.) As some of the livers of the meat hybrids were quite streaky, I'm concerned about the combs in case they're a sign of jaundice. Then again the faint yellowing might be the chilly weather or something else entirely.
According to Wikipedia the alkaloids and other naturally occurring toxins in the legume produce neurological damage rather than liver disease. As I'm seeing no signs of neurological damage I might as well cease cooking the lupins. EDIT: See end of post. The question remains whether mould toxins are causing liver damage in my birds.
Other sources mentioned that the mould toxins tend to be confined to stems and leaf matter. This is unlike wheat where mould toxins are able to permeate the entire batch from even very low levels of fungal infection. Apparently only discoloured lupins have been found to have undesirable levels of mould toxins. Having looked more closely at the lupins I would say there is very little stem material (perhaps 0.1%) and only a small percentage of discoloured beans (roughly 0.5-1%).
Furthermore, if any of the birds were going to look jaundiced it would surely be the meat hybrids, which eat massively more of all the feedstuffs the birds are getting. None of the girls are showing any comb discolouration at all. I know this is tempting fate, but the bird below is typical of the meat hybrids (with the exception of the one currently in a cage for a foot/leg problem), and I feel the bird below is the picture of health:
Here is a side shot of one of the girls, showing their enormous body size.
It's hard to imagine they could achieve this growth (without huge fat accumulations) on a diet that kept harming their livers. The birds all (even the cockerels) behave normally and have good bodyweight for size. Perhaps I should trust that and just keep tweaking the diet according to any new information, without giving up the entire project. After all, if we can't learn to sustain our animals without relying on mega-science, how will they survive if things change?
A change of heart. For now, I will keep cooking the lupins. Diets containing up to 10% lupins are associated with wet, sticky droppings, though according to the above sources this doesn't harm the birds. But having just realised how firm and healthy looking the birds' droppings have become since moving to the cooked version, I'm wondering if the slimy droppings mean something more ominous for chicks raised on lupins? After all, it's unlikely the research was done on small chicks. (Incidentally sorghum is an example of another common poultry feed that can depress growth in young ones.)
Even though my birds are close to maturity, it makes sense for me to continue the processing if it helps their droppings seem more normal. As I've said earlier, it's easier to cook lupins than it sounds, and I can always move to the extruded lupin product from my local feed store if I get lazy. In particular I'll keep cooking lupins for the youngest birds, and see how my next batch of growers fare in terms of overall health.