URI/Upper Respiratory Infection 4 and a half year old boy keeps getting Rattle noise...

Chester boy has been in the rescue for nearly a year...he has already gotten this rattle noise (NOT wheezing or Hotting)3 times before...the vet checked his nose, eyes and lungs...no other signs that is a URI but she gave us baytril and with-in 7 - 14 days each time it stopped....it's always about 3 - 4 months between him getting it.

3 weeks after he come to us he was introduced to Jasper (a boy found in a park)...now Jasper has never gotten sick and we've never separated him from Chester so I'm doubting now it is a URI...more so that I've never heard him wheez but it's a rattling noise that from memory (remembering the last time he it it was months ago) it comes from one of his lungs....but always the same one.

He never loses weight.

I'm probably missing a common sickness that involves rattling in one lung...but the fact it keeps reoccurring? He was even out at foster home and it came....so he came back and went on Baytril.

Him and Jasper just keep coming back to us....It's as if they've decided the rescue is their home and each time someone comes around to meet them they mess-around and become little brats!