Having just completed this game, I thought I would share it here. I grew up playing Lemmings on my mates sega, and I have countless memories of staying up to the small hours playing level after level. I just loved the problem solving nature of the game!
Any way, I found this game here (chicks) whilst browsing the app store, and all my childhood memories returned. Similar to lemmings, you are in charge of a brood of chicks, and the tools to get them safely home are at your disposal – builders, diggers, tunnelers, climbers etc.
With 32 levels, this game is definitely addictive but also well made and challenging. At the moment it's free on the app store, but even it if wasn't I would still buy it – it's that good!