Secret Bunnies

There are 16 bunnies hidden in the well. They are required to solve the BDTP puzzle after collecting all 64 eggs and reaching the second ending. All the flute songs can be found on the page Secrets.

Locations

Bunny #3.

Hint for bunny #6.

Solution to the wall mural puzzle.

1. Wall mural bunny: One room to the right from Mallard, there's a wall mural of a bunny. Using the Remote in that room detonates the explosives and reveals a hidden passage to a control panel that allows you to change pixels on the mural. If you continue through the secret passage to the room below, you will find one of 50 unique puzzle pieces. The puzzle piece is different for every player. After finding all 50 pieces and solving the puzzle, you can then paint it on the wall using the control panel, which spawns a bunny.
2. Vine bunny: In the upper right section of the map, go to the dark room that's two rooms down and one to the right from the heart shaped room with the telephone. There you can use your mouse to move the vines and reveal barely legible arrows on the wall behind them, that correspond to a song you can play on the Animal flute. Play the song and summon a bunny.
3. Tutorial bunny: In the room with the Great Egg, there is a fake wall to the upper right. This leads to a room with vertical shafts and spikes along the walls, with water at the bottom. You can do this room with only the B. Wand, but it's easier with the B. B. Wand. First off place a bubble and let it sink near the water, then you can start moving to the right to the other shaft. Now use bubbles to climb up and access the next shaft. Sink again with a bubble and use bubbles to get over to the right to the exit. The bunny will be right there, you probably noticed it as you were getting out of the starting area.
4. Pillar bunny: There are pillars in many rooms with a stamp symbol and a number of dots. For each symbol, connect their locations on the map screen in the order of the numbers. When completed, they form the numbers 67234353 across the map. Play this on the flute to warp to a bunny location.
5. UV bunny: Can only be seen with the UV Lantern and can be seen moving up the ladder where the Mallard is. Can also be randomly encountered in some other rooms. If you see a random but unexplained sparkle, try to equip the UV Lantern and follow the trail.
6. Fish bunny: Three rooms left from the central Telephone, play the Animal Flute in the sequence hinted by the UV markings to reveal a hidden trapdoor leading to a secret bunny.
7. Ghost bunny: In the starting area next to the firecracker room, there is a ghost that cannot be defeated with a candle. Its face changes over time. The faces correspond to the numbers 12345678. Play this on the Animal flute to transform it into a bunny.
8. Crow bunny: Go to the room above the room with the bear head in the upper right section of the map. There are eight crows who make sounds that correspond to the eight notes you can play on the Animal flute. Playing the corresponding song on the flute unlocks a secret compartment with a bunny.
9. Mallard bunny: Go to the room all the way in the upper right corner of the map. There's a sequence of faces on the wall, which correspond to the notes you can play on the Animal flute, as per the diagram in the skull room. There's also a picture that can be either a rabbit or a duck, depending on how you look at it. By using this hint, you can deduce that you're supposed to go to the Mallard and play the song, which transforms him into a bunny.
10. Dream bunny: Simply stand still and the player avatar will sleep eventually. A dream bubble will appear with the secret bunny. Simply wake up and touch the bunny (I was in the room with the chest containing the map when it happened, but it probably works everywhere).
11. Bulb bunny: The firecracker room before the ghost has a mural in the background with a bunny and four bulbs of three different appearances. The bulbs correspond to the bulb you come out of at the start of the game, which is different for each of the three save slots. Each bulb makes a different melody and spark pattern when it opens. Play these melodies in the mural order on the flute to warp to a bunny. The complete song is 1357136813572468.
12. Floor is lava bunny: In the room with the three dogs, there's an inaccessible passageway blocked by two layers of switchable blocks in the upper right corner and they cannot be switched by using the remote in this room. To get to the other side, you need to stand behind the first layer, jump, switch the blocks an odd number of times, and get in water without touching the ground. The easiest way to do that is to get to the water two rooms to the right by using the Disc, the Remote and the B. Wand. Hint: standing on switchable blocks doesn't count as standing on the ground. Jumping in water then teleports you to the last place you were standing on the ground, which was behind the first layer of the switchable blocks. If you've done this correctly, the first layer should now be solid, and the second should be open. You can then go into the secret passageway and find a button which opens a hidden compartment with a bunny in the three dog room. Alternate method.
13. TV bunny: In the skull room, a diagram can be found with eight faces corresponding to the eight notes on the Animal flute. Go down from the skull room and into the house. Using the remote on the TV shows the eight faces in a particular order. Play the corresponding song and spawn a bunny.
14. Barcode/Origami bunny: In the dog bowl room, the grass on top of the bowl can be scanned as a barcode and gives you the code 18756753, which corresponds to a song you have to play on the Animal flute in the same room, which opens a secret passage with a bunny and also a chest that contains a figurine mama cha. The same numerical code can be found in a more convoluted way. In the peacock room, examine all 64 eggs with the UV Lantern and discover the secret song. Playing it unlocks a secret room with a chest containing the Office key, which lets you unlock the locked door in the house. In that room there is a computer. By interacting with it, if you have a printer connected to your computer, it prints out instructions for an origami bunny, and by folding the paper, you get the code. Playing the song in the Office then spawns the same bunny.
15. Ghost dog bunny: Pick up the Mock Disc and go to the room with the bear head in the upper right section of the map. Go one room to the left and one down. There's a dog bunny statue on the right of the room. Lure the ghost dog to the statue to transform the statue into a bunny.
16. Spike bunny: In the upper left section of the map, above the swordfish lake, there's a secret passage that leads to a room with spikes. It is possible to get through the room by only using the Disc. Throwing the Disc at the very top of your jump lets you ride it instantly, allowing you to get past the spikes and onto the next floor. Repeat this three times and get the bunny at the top.

There are also 9 bunnies that can only be found by hacking the game. These are meant to prevent players from solving the BDTP puzzle by hacking.