BRUSSELS (Reuters) - The European Union needs legally-binding rules to oblige zoos to keep wild animals in acceptable conditions, the European Parliament said on Thursday. The EU's directly-elected assembly said animals in many of the estimated 1,000 zoos in the 15-member bloc were poorly housed and fed. A survey commissioned by the EU in 1988 found "a considerable number (of zoos) met none of the accepted minimum (standards) and could best be described as 'animal slums'". EU governments have said animal welfare is best dealt with under national law but Euro-deputies insisted this was not enough and demanded legally binding EU legislation that would force zoos to meet specific animal welfare standards before they could get a licence to operate. EU officials have said they are not optimistic that EU ministers will change their minds.