The price discovery structure for eggs used for manufacturing purposes in Canada has been pretty much the same for the last 25 years, and is based on the Urner Barry (UB) index. However, eggs used for manufacturing has evolved during the same period, from a marginal 10% of total egg consumption to currently more than 30%. Thus, the representativeness of the UB index is an important issue for the Canadian industry. The representativeness has been questioned in the past in the US and Canada. This study focuses on the representativeness of the UB index by looking at causality links between the ECI spot market and the UB index. Our results indicate a good representativeness and seem to indicate a complementarity between the ECI and UB.