I cannot find any scientific explanation for this theory and am of the opinion that as long as a cock can fertilise an egg or a hen can lay a healthy egg, the youngster hatched from such an egg could develop into a perfect pigeon.
One could even write a book about the number of Champion pigeons that have been bred from pigeons of 10 years old and older. It is perhaps a good idea to mate an old pigeon with a younger one, but I would not say that it is essential to breed in this way.
One should take care not to allow an old pigeon to rear its own youngsters, since old pigeons are inclined to develop less pigeon milk than their young counterparts and this could be one reason why youngsters reared from old pigeons develop less vigorously. Old pigeons also lose condition if they are required to feed youngsters and should therefore be assisted. It would therefore seem to be a sound policy to make use of foster parents when rearing youngsters bred from old pigeons.
When Gerard Vanhee visited South Africa early in 1972 hè did not hesitate to buy the Old Crayone Oscar Devriendt cock Belg 59 3370943 from Aad Lockhorst and take it back to Belgium, The old cock was 12 years old at the time, yet hè did not hesitate to pay R 200 for it.
However, it is common practice among fanciers to retain the youngsters bred from old pigeons for stock purposes, rather than to race them.
Old pigeons are only kept because they are or were good, and have, in most cases, given proof of their ability to breed. In the Old Crayone's case Gerard Vanhee certainly did not expect to breed a racer out of him like his Grandfather, "De Zwarteband" of Oscar Devriendt, but hè certainly expected to breed another son from him like "De Schone Blauwen", father of Pol Bostyn's famous "Benoni".
His youngsters would therefore be carefully tested for proof of breed ing ability, and if one of them is found capable of breeding outstanding racers, then Belgium's Champion fancier will certainly have made another investment for the future.
For this reason I would always be prepared to breed from an old pigeon, provided that it is still healthy and has proved its ability to breed outstanding pigeons.