If she'll eat, feed her. It won't hurt the antibiotic therapy. Just be careful that an injection isn't scheduled within 24 to 48 hours after feeding her - you don't need the hassle of dealing with a regurge/vomit while she's recovering.
Ceftazidime is every third day - right (ETD on the label)? If that's the case, I'd try offering her food no more than 12 hours after an injection. That gives her over 48 to get digestion under way before she gets another one.......
If she doesn't eat what's offered fairly quickly, don't tease feed her or mess around too much.
I'd recommend keeping the humid hide as a permanent fixture.