I have a 9 mnth old boa. She has had some strange syntoms ever since I had the incident with a heat pad burning one of my tubs. The snake that was in the tub died not long after. There was fumes from the plastic burning that lingered for days. My snakes are in the basement and it was winter so couldnt really air the place out very well. Anyhow the boas tub was very near by so I think she ended up breathing alot of the fumes. Now she has ri syntoms, sometimes. Its strange she will have the crackiling and then sometimes would open her mouth for a gasp of air. She has not ever shown any other syntoms. No mucas, no holding up her head. She has as big an appetite as ever and sheds no prob. So i bumped up her heat and humidity and the syntoms go away, then they will come back. So I think about a vet appointment then they go away agian. this has been ongoing for a while. she will be fine for a period of time then for a few days she will show syntoms then they go away. Just this week I planned to get her an appontment she had the syntoms then last night they were near gone agian. My concern is that ill get an appointment which you have to wait for then take her in and shell be fine. Then get charged for a vet to say shes fine. I cant get to a vet it seems at the same time she is showing syntoms.