Rooster wheezing badly

[Sunny Windsong]

Help!
My cemani rooster is wheezing badly! We had a crow collar on him and I thought that might be what was wrong so we took it off but today he is still wheezing and it sounds like he is struggling for every breath. However, he's not showing any signs of lethargy or illness. Could something be caught in his throat or his crop? I have put tetracycline in his water along with oregano. About a month ago he had a gurgling sound whenever I would pick him up. But as soon as I would put him back down it would stop so I thought it might have been a defensive tactic to try to get me to drop him or something. But then the gurgling completely stopped and now this wheezing? I'm about to go out of town and leave my husband in charge of all the birds and I'm really reluctant now.

 

[Little Chicken Girl]

... I know this is going to sound really, really weird... but if he is showing no signs of illness otherwise, I would try feeding him a piece of bread (broken into small pieces) soaked in olive oil:

I have had several hens (over the course of 4 years) that began making gasping noises and seemingly having a hard time breathing (which turned into wheezing)...
After inspecting them, I was puzzled at what could be wrong (they otherwise appeared in perfect health). I was searching online for a diagnosis when and heard that feeding them a torn up piece of bread soaked in oil (then gently massaging/stroking their throat/crop) would solve it. I thought "Well, I guess it can't hurt to try..."
So, I did it once in the morning and once in the evening (1/2 piece of bread + olive oil each feeding) and gently stroked the bird's throat... A couple times, the bird was all better before finishing the first 1/2 piece in the morning... I have successfully done this 4 times over the years (with different chickens) though I have yet to find out exactly why it works.

UPDATE: Found out why it works (for anyone who is interested). Impacted crop:
When the crop is impacted, it will continue to fill, while emptying slowly (if at all) and can put pressure on the trachea (windpipe), causing the bird to 'wheeze'. Bread and oil often solves the issue by breaking up blockage. I further read that limited scraps and plenty of grit helps prevent crop impaction. However, my chickens have all the grit they need (their run consists of sand) and they only get a few scraps in the morning. However, it did not completely prevent it from happening a few times.