I have had mixed answers about this plant. I was wondering if anyone has put these in the enclosure. They are apart of the cactus family of that helps!
This would be senecio. Most plants in this family are toxic.
From Dave's Garden:
"As a group, Senecios are one of the more toxic plants and have been known frequently to cause significant toxicity in farm animals which eat groundels and ragworts indiscriminantly.However specific cases of toxicity from any of the succulent species are very scarce and I could not find a single reported toxic exposure to one of these plants in my searches for one.However, avoid putting pets and children at risk as some Senecio species have potent liver toxins; it is better to be safe than sorry."
I agree with Yvonne; most African succulents like this are poisonous, at least as a regular diet item. No poisonous plant references I have list the three species commonly called "blue calk fingers", but that does not mean they are safe.
I think there may be some (understandable) terminology confusion. Ragworts and groundsel are now Packera spp. , or Lingularia and although previously listed as Senecio, would not necessarily be relevant to Blue Chalk, which is now Senecio, but used to be Klenia mandraliscae and native to S. Africa. Either way, these are Asteraceae, not cactus.
Kew has a nice treatment of the composites if interested.
Regarding toxicity, I can't offer a definitive answer, but on balance would recommend against it as there are too many other good choices. Hope this is helpful.