We have the same sort of stuff you get in the USA. I think the only difference is there is still quite a lot of fish based feeds further South. I was very disappointed when the local mill discontinued it due to cost.And I have no idea what's available in commercial feeds in Spain!
Almond juice isn't milk!
Many people can't manage lactose after childhood, even if they could earlier. Especially cow's milk.
I did know three children, siblings, your contemporaries, who had anaphylactic reactions to peanuts, and it wasn't pretty.
Wonder bread? You bet! It was awful!
Nobody knew the cause, or had a name, for celiac disease.
I do think that there are more allergies now, and there's data showing that raising children in too 'clean' and environment ain't good.
It's well known that pet rodents, and pet birds, and chickens, can have issues with whole seed diets. Not all of them, but a fair number of individuals will eat the best tasting stuff, and leave the rest, causing malnutrition in those individuals. That's one reason that I prefer to feed a crumble or pelleted feed, with a recent mill date.
Mary
I am the only person on this mountain that feeds the chickens commercially produced feed. I get the Micky taken out of me at just about every chicken club meeting we have about this.


Some here make their own feed, often meat or fish based. Others don't officially feed their chickens at all. The game fowl breeders here are extremely fussy about what they feed their fowl with. I'm waiting for a recipe from one guy at the moment. His family have been breeding game fowl for 5 or 6 generations. Unfortunately in the past they were bred to fight. Thankfully it's illegal here now but they still breed.