Good job for a 24h hour game !
The game feels unfinished (and it is apparently, since it's missing 3 levels).
Two very important things I think you should rework to make the game more enjoyable :
The collisions - You should have chose a square or circle shaped collider for you chick. Sometimes it feels as if it follows the shape of the sprite : that's not really good for performance (for a small 2D game that's actually not really a problem) ; and for game play : when I missed my jumps, I sometimes stayed stuck on the edge on a platform, surviving thanks to my belly, but couldn't jump or go any further (I had to commit suicide).
The horizontal movement - Your chicken doesn't know how to slow down! Once you pressed left or right, you chicken will keep on running for a while. You should add a faster "slow-down" when no key is pressed : on each update, if the chicken is on the ground, and no horizontal key is pressed, divide the speed by a value close to one (1 + updatetime*something) /or/ set the horizontal speed to (rightKeyPressed-leftKeyPressed)*speed (a bit too violent I think). Do something like that, because right now it feels like the chicken is on very slippery ice.
Some other things that could make the game better :
Add animations (you planned on doing it but couldn't, I understand), effects (particle effects following the chicken, hen, or egg for example), and visual indicators. I don't really know where I re-spawned most of the time because all the platforms look identical. Add a palm-tree here and there, dry grass, etc... Could be cool.
More graphics in general would be could. Be careful of not-so-compatible colours. (I'm thinking of the desert level where the chicken's bright yellow, the orange of sand in the background and the platforms' brown don't go so well. Try taking either colours that are far enough from each other, or take colours with the same "hue" and close "saturation".
Reduce the length of the not difficult parts. Sometimes you have to get from one "puzzle" to another, and you have empty horizontal platforms : remove some of them. It will make the game more dynamic. It's also true for the end of the second level, where you have to run for a month (measured it) to reach the end.
I felt like you had a lot of very good varied idea, but it wasn't correctly executed. I saw variation in gameplay (the hen part for example was very good) and it was cool.
Good job to you two ! I wish you good luck on your future projects ! I hope you'll be able to spend a full 72h for the next ludum dare.