I have sat for hours with Eddie Newcombe talking on the wings of pigeons as this was eddies theory and he was telling me about having birds put to him while at shows on panels and 9 times out of 10 he got it 100% correct on the one occation he was wrong the bird he put as the distance bird had not been raced over 300 miles so he was picking sprint ,middle , long distance birds on the wing makeup.A youngbirds wing is completly diffrent from an old bird take a picture of a youngbirds wing then take a picture of the same wing a year later and look at the diffrence in the wing