Can facetime be used in a conference call with more than two people

No, FaceTime does not offer conferencing.

iChat Theater had that available, and Skype and probably a few other packages do offer conferencing.

With iOS 8 FaceTime audio is suppose to, but there still seems to be problems. This is a more recent thread related to FaceTime conferencing: Does iOS 8 FaceTime have audio conferencing or not?

Now yes. with FaceTime Audio, but the fonction still not working in 8.3. Please refer to the main post : How to add caller to Facetime audio call in ios8?