After weeks of trying to find where I had gone wrong I re downloaded the piface image and had another go at my version of the twitter chicken, however this time with a furby and sure enough it works.
Sound occasionally gets interference but I expect that can be solved easily.
With the hash tag furbtwit and when the piface is turned on it will look for tweets with the hash tag before reading it out. And dance to it. I've done a video just need to find a way of adding it to this.
Update here is the link http://youtu.be/jVE5G-r3hzc