rose hips contain tiny hairs around the seed. these are highly irritant both to skin and nasel tissue if inhaled, and should be removed befor consumption. (at least when fresh) im not sure what effect drying has on them though when you make jam it just be strained again and again through muslin so presumably the hairs are resiliant to high tempratures.
unless you are buying seedless rosehips (ie..seeds removed) i would avoid feeding these to rabbits