Sunflower seed and black oil sunflower seed are indeed not the same. They may be higher in protein but they are also fairly high in fat so I wouldn't over do them either. Your scratch will be fine as a treat once you get them back on track.
I think my birds prefer scrambled egg over boiled. All birds are individuals and so trying things and seeing what works for your flock is OK.
Dehydration will kill you rooster faster than not feeding.
While I'm thinking about it... your birds don't free range, what kind of grit do they have available in their coop? My birds have plenty of access to gravel on the ground and such. But depending on your ground you may need to provide some sort of grit because that is how they digest things.
Other things that are OK to feed and have protein are yogurt, cottage cheese, cheese (in moderation, salt content), cat food. But I'm not suggesting to over load them on protein just to get them back on track is all and make sure it's balanced after that. All though I do feed extra eggs, they also are high in fat so I don't do it all the time. Same for meal worms. I also raise my own and it takes WAY longer to get going good than I prefer. But my temp is fairly low (60) so I'm sure that has an impact on time frame.
Chickens are creatures of habit. So sometimes it will take them a while before they try something new. Might even take a couple of introductions. I think scrambled eggs are yummier than boiled because of having the yolk mixed in with it all. The boiled white is kinda tasteless to me. As far as bacon or ham goes, I think they are too salty and processed. Plus they gonna have to fight me for the bacon!

Yes, I'm not surprised they are mad you took away the scratch. It's tasty and you're changing up their routine.
For your roo, I might go ahead and offer a raw egg yolk. That's what chicks are born with as their source of life for the first few days after hatch. It should be easy to digest and loaded with nutrients and micro nutrients. Often a last ditch effort to help a recovery.
When they are under the weather they can have a harder time staying warm. I think you did the right thing by bringing him in.
Also, the nutrition may only be one part of the story...
How long ago was it that you had a couple of 5-6 month old birds die? What symptoms did they have? I'm not familiar with Tylan, but the wheezing does indicate something more. When immunity is down all kinds of illnesses might flare up and take advantage.

I think the Tylan is an antibiotic. It MIGHT help to fight off any infection or secondary infection that may develop. You will either have to use what you know or wait for someone else to give you a more informed opinion on that one.
Hope he feels better and your girls continue to show improvement!
