I have four grown chickens that free range with 4 nubian/boer mixes, (2 of which are 150lbs) + and one Suffolk ewe( she is huge! apx 250lbs) They all do fine together. I would just make sure that if they are in a confined area, not sure how big your fenced area is, that the chickens have a way to escape goat hooves. As I am sure you know, goats don't really care who or what they step on if it is in their way and they want to get somewhere(or even worse, are scared and panic). As stated above, I too, would also make sure the chickens aren't pooping in the goat feed/hay as well. I think keeping goats, as well as chickens, on a regular worming regimine is a good idea anyway, and you wouldn't have to worry too much about worm problems.
Hope this helps, good luck!