Many years back before we had all these different feeds, feed for sprint or long or with this in that in, i spoke to an old fancier (and a Dr) and he basically told me this:
Every species of animal has an in built programming of what a balanced diet is, the only species that has lost these instincts are primarily "the human race" and any animals it has domesticated, although there is still a small piece of this instinct left in there, like a womans craving when pregnant! Racing pigeons come into the domesticated range, as they are basically only usually fed what its owners feed them! But when the range becomes wider for them as in some variated mixes, they may well start to leave a particular seed. That is a little clue to how there system is coping, they are not eating it for a reason, but lo and behold many will make them eat it! As much as we like to think these mixes have "X" content of this and that for our pigeons, the only ones that really know are the birds themselves!
My point on this was that but surely if our birds need to fly a certain distance then surely they need extra this extra that to be fit and conditioned? His reply who feeds the wild birds, what is the greatest fitness of them all- natural fitness, swallows etc being the greatest example of this having to feed themselves and fly 1000's of miles.
His final point being that how many birds do you see that work home after a good period out (not just a few days) after a hard race come back unfit and uhealthy? Most are usually fit enough to go back to the very next race!
What do you think?