There are five keys in total to find but the very first one you can access with limited skills and story progression is in the lower entrance to the Templo de Jade. After escaping the Prison de Corazon you'll have everything you need. Leave the village of Pantanillo in Los Manglares to the right and access the temple through the entrance below the dimension bridge and to the right. You will pollo glide over an acid pool just before entering so you know it's the right one.
You'll now begin a viciously paced platforming section that can be quite difficult. The key is to keep moving at full speed but it is possible in one or two sections to go "too fast". The sliding dimension bands should keep you away from the lava if you maintain the proper pace. If you think you're falling behind, remember you can switch to a chicken to run faster and catch up. As @Schinderdiv mentioned in the comments, you can run through this section as X'tabay since she is faster than Juan it will prevent the need to switch to a chicken to catch up.
For the vertical conveyor belts, @sm4k mentioned in the comments you do not need to jump at the top as the belts will launch you into the air. I personally did jump but this could be an alternate method for those that want a few less button presses during this sequence.
You'll run, jump and Eagle Boost to the right, then left, then right and will need to transform into a chicken after jumping down a larger ledge to continue. Then you'll continue right, then left, then right, then left before turning into a chicken again for the small space and chicken gliding right afterwards. A few more jumps and Eagle Boosts and you'll reach the end with the egg. Punch it a few times to get the key and the achievement will pop.