I noticed today that one of my chickens seemed to be having a hard time breathing. I picked her up and heard her wheezing. Now, she isn't gasping constantly, just when I pick her up or when she starts moving around a lot. I tried looking down her throat to see if I saw any worms but as far as a could see she looked clear. I didn't see any nasal discharge. I went ahead and gave her a Tylan 50 injection today to be sure, but I was wondering how I could tell if she had gape worm or an infection/virus? I didn't see any worms, but they may be down too far to see. And I'm not seeing any discharge. Any symptoms to look for so I know for sure what she's got?