What I have found is they will eat about anything, and if they dont like it they wont, typically they wont eat anything that doesnt sit well with them. of course that may just be my chickens, ducks, and turkeys.
NO on the elephant ears. If they bite into a leaf they will end up with many many little tiny spines in their mouths, crop, etc. While this most likely won't kill them it will be extremely unpleasant and may keep them from wanting to eat for a few days.
Hello- new to the site, new to chickens, but gardening I know!
NO MORNING GLORY!! I suggest you wear gloves when you handle it, and don't put it in the compost bin- you will end up with morning glory growing in the bin and then in your garden where you don't want it.
The ipoema (morning glory) plant has an hallucinogenic property in it, similar to LSD. It can give humans a nasty headache from handling the vines. I can just imagine those poor chickens if they eat it- What to chickens 'trip' on anyways?