Chickens were domesticated out of Asian jungle fowl, probably twice (in the indus region and Burma according to wiki) and spread westward. They arrived early enough to be a part of Roman culture and divination and appear to be an assumed part of domestic life in prechristian times in western europe. They are hardly suitable for trade, since they require live cartage and care unlike walking livestock. They are non-migratory and at best semi or full forest dwellers when undomesticated, their presence supposed trade or human migration. I'm assuming migration? Would we know if they were traded?
Tea was in use in Asia in the 2000bc period and is a highly portable dry good if high value, less than pepper but undeniably tradeable. We know some very high value artifacts traded through Asia and reached western Europe.. so how come we got chickens, which are possibly the least tradeable item but didn't get tea until far later?
I'd like to see more on this. I believe genetic analysis could be used to trace the migration pattern (if there is one) to give evidence of that thesis. I wonder if anyone has ever done it?
There's a third possibility - spread of chickens by a slow process of repeated short-range trade. Instead of moving them across a chicken themed silk road, they are simply traded (or gifted) from village to village until they spread from the Indus to the Seine.