Honeysuckle berries are SUPPOSED to be poisonous. But my hens have always eaten all, and I mean ALL, the red honeysuckle berries they can get their beaks on. Even jumping and nearly killing themselves trying for the biggest bunches at the top of the vine. We have lots & lots of honeysuckle vines. Smells nice, feeds the bees during blooming, and the chickens eat the ripe berries in fall. We also have lots of different plants you'd consider poisonous too, like lily-of-the-valley which people say you should get rid of if you have a dog. Not my chickens. They even graze a teeny bit on the leaves. We also have nightshade vines, and they eat the ripe berries on that, too. Chickens are amazing. Early February, my hens were eating the growth tips on the fronds of our cedar trees. All spring they have trimmed the bottom skirt off my weeping maple, as high as they can leap. They love to eat the leaves. Darn tree looks weird now.
I agree, if they have free-range access to lots of different shrubs/weeds/plants/grasses, they will be fine. Birds know what they need, and from time to time they "medicate" themselves with even some stuff we consider poisonous. (come to think of it, so do we!) I do worry for the birds that are confined & have only access to one or two plant types, because they will get a toxic overload if that is ALL they can get. They need seasonal variety. Your chicks will LOVE weeds.