That's one of the good things about this forum, isn't it - i.e. , we're all learning from each other all the time. When I got my first chickens, back in the 1970s, i had nobody to turn to for advice, there was of course no Internet, also no poultry keeping magazines, and our local bookshop and even the Public Library stocked nothing on chickens. I did buy one book by post, without the benefit of any reviews like you get nowadays, but it was really boring and useless. How our birds survived I really don't know, though they did live long lives and laid well, despite what I now realise were rather overcrowded and dirty conditions. I had a break from chickens after that, and then returned a few years ago, to find a whole different world of help to get started again on poultry keeping. For one thing, plastic coops had been invented!
So do you think an ordinary person, not a vet, could drain a crop easily and successfully using a tube? There are circumstances where crop draining could be a necessary emergency procedure, and whilst I have done it without apparent ill effects by holding the bird upside down and massaging the crop in the classic fashion, I wouldn't know where to start with a tube. Would you perhaps have to insert the tube and then suck to create a siphon effect? (!!!!) it does sound quite invasive to me, compared with the previous method.