As Andy said, I think it's hard to compare pigeons from different countries as each of them are flying in very different conditions, as I young lad starting out I remember being told that if you want to succeed, get your stock from fanciers who are regularly scoring in the same events/conditions that you want to compete in. One example of this was for distance day birds, when flying on the North Road from Thurso or Lerwick, I was told to look for birds that had flown 500+ miles North to South and not South to North as the day light hours in the North are far longer than here in the South.
As for those supplements, I think its definitely each to their own, all those products are available from most uk pigeon pigeon product suppliers and I'm sure some do make a difference. The only thing I would say is that most of these are pretty similar if you look into it and can almost certainly be made up much cheaper from natural products you can buy off the supermarket shelves. I remember fliers, again back when I was a lad who used the likes of Iodine, yeast, lemon juice etc on their feed or in the water.
As for modern feeds they are just mind boggling lol and even as an ex stockman myself I wouldn't know where to begin in pulling these apart lol. I do however know that a lot of local fanciers do like to use a fair bit of hemp these days, it is another expensive extra though.
As I say, each to their own, if it works for you and you can afford it then good luck to you, the main thing for me is to just enjoy being in the game

Just my opinion
