The Eagles have struggled for goals this season with just 23 to their name so far.
The Eagles returned to scoring form in the weekend victory against Southampton in the FA Cup, as they won 2-1 to progress to the fourth round.
They have generally been short on goals this season though, with just 23 to their name in 20 Premier League games so far.
Indeed, their top goalscorer in the league is central midfielder Yohan Cabaye, with five goals to his name.
Connor Wickham is their only striker to have scored with one, and Millen says improving their end product is something they need to work on as a side.
"End product from all our attacking players, whether it's creating goals or scoring goals," Millen highlighted as an area to improve to the club’s official website.
“We need more people scoring goals, we've not scored enough goals throughout the squad.
“That's where we've been lacking, it's the only thing - maybe - people can criticise us for: our forward players haven't scored enough goals."
With Palace’s strikers struggling so badly for goals this season, it would not be a surprise to see manager Alan Pardew push hard for a new one in the January transfer window.
Palace are currently seventh in the table; just a point outside the top six and five away from the top four, meaning a place in Europe is very much up for grabs this season.
A striker who can get the goals they need could help propel them up the table, and one is sure to be top of their manager’s wish list this month.