mean： to be hopeless at sth, 等：wait 公鸡：the rooster 下蛋：lay egg 没：not have 指望：hope Actually, the second sentence "没指望" is the expression of the first sentence “等公鸡下蛋” . like 'it couldnt happen in a million years'. děng(等) gōng(公) jī(鸡) xià(下) dàn(蛋) ---- méi(没) zhǐ(指) wàng(望) ex： A：你爸妈什么时候给你买手机？ B：我看今年是等公鸡下蛋——没指望了。 A：when will your parents buy you a mobile phone? B：i dont think that could happen in this year. the sentence like this called 'xiēhòuyǔ(歇后语)' in chinese: a two-part allegorical saying, of which the first part always stated, is descriptive, while the second part sometimes unstated , carries the message.

deng3gong1ji1xia4dan4---mei2zhi3wang4, means hopeless, impossible

I start do doubt the wisdom behind the saying after seeing this article: http://www.dailymail.co.uk/news/worldnews/article-1267691/Gianni-gender-bending-rooster-starts-lay-eggs.html

It means hopeless,impossible.When someone promise you something,but you don"t trust sb,you maybe say it.

děng(等) gōng(公) jī(鸡) xià(下) dàn(蛋) ---- méi(没) zhǐ(指) wàng(望) mean something that never ever happen