So recently my juvenile redfoot has started making a strange sound every so often that worries me- like a cough or a throat clearing type of sound. He does it a few times every few hours and then stops, but this has been going on on-and-off for about 4 days now. He doesn't have any other symptoms of a respiratory infection (he's had one before that was treated, and this isn't similar to that at all) and he's eating and drinking as normal. The only other thing I've noticed is he seems a bit lethargic lately, as usually he wants to run and climb on anything around but as of late he's been sticking to staying in his hide. His humidity and heat have been at normal levels, so I'm not sure what's causing these noises? Does anyone have any idea what might be causing it/what it even is?