I have also noticed that Dills appetite has been really off this past week.
We have not had really hot temperatures though, so I can't blame it on that.
For a while now, I've been bringing her home mulberry leaves, and for whatever reason this past week, she's been pretty much turning her nose up at them. Normally, she will lunge at the leaves, and you have to be very careful she doesn't take your finger tips when she bites the leaves. She's VERY enthusiastic about Mulberry!
Anyway, the other night, she was eating some leaves off of a mulberry branch. She didn't seem to be having any difficulty with them, and I stood right there watching her...just because I love to watch her munch her way through the leaves. She seemed to have eaten her fill, and turned away from the branch, so I left from in front of her cage.
After a few minutes, I heard a sound and thought it was one of my cats coughing up a hair ball, as that's exactly what it sounded like. It turns out it was Dill. I don't know if she got too much leaf in her mouth, and couldn't get it down (mulberry leaves can be a little course, or picky) and was trying to cough it up, or what was happening. It scared the bejeebus out of me though, I can tell you that! I've never heard a skink cough before...or any lizard cough, for that matter.
She did her exagerated swallow that PTS seem to do, and coughed a couple more times, then seemed to be fine. Since that day, I've been watching her like a hawk, looking for any signs of a URI, or other indication of trouble.
That was only the second time she had eaten this week, and she hadn't eaten since that day, until last night, when I dipped a huge pothos leaf in warm water, and held it in front of her. She plowed through that with no hesitation, and had no difficulty swallowing it, and no coughing episode afterward.
So...I don't know if now she's gone off of mulberry leaves. Or if she thought the big pothos leaf was more appetizing, or what. She has Pothos in her cage at all times, and also two different water bowls to drink out of, but for whatever reason that pothos leaf last night really got her attention. It was off of a plant that is not in her cage, and the leaf itself was bigger than my hand..so perhaps it had a more intense smell to it or something that made it seem more appetizing.
The only other thing I can think of that has put her off her food is, I noticed last night, when I was rubbing her back, that she is going to shed. Her skin on her back was really dull, and loose in areas. If that's not it, then the only other explanation I have is that she is just being finicky, or plain and simple isn't hungry right now.
So...after all that long winded story telling, I have no specific advice to offer...except just keep trying. One of these times something in bound to catch their interest.
In the past, I've noticed that if I ever so slightly warm up her food, not hot, just a tiny bit warmer than room temperature, she will show much more interest in it. Especially if it is something that has a strong smell to begin with, like cantaloupe, papaya, or sweet potato baby food. Often I will puree one of these foods, and pour it over her chopped greens.
That is always met with approval.
Do you chop your PTS's food up? I chop Dills food (other than the leaves I hand feed her) in a mini food processor, until it is the consistency of "chopped parsley".
And in the meantime, if you're worried about their health, a trip to the vet is never a wrong choice.
Trust your judgement, and good luck to you and your PTS.

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Kim