So I was sick of all the wasted food from my chicks and decided to get creative. I used the carton from the goldfish crackers my kids had just finished, 3 paper towel tubes, masking tape and a binder clip.
I cut 6 rectangles around the box, alternating 1 door, 2 doors, 1 door, 2 doors because I was worried about the space of the tubes inside and the stability of the box if I cut too much off. Don't cut them too low or it won't keep the food in for you. Sorry I didn't take actual dimensions.
Through trial and error I found I liked the paper towel tube cut in half because even cut in half they are longer than the TP tubes so I could add some more food in the middle of the box. Cut a rectangle a little taller than the door on the box but so the tube is also sitting lower than the opening of the door while not touching the bottom so the food can get under. (sorry about that description) I also cut little notches to try to help hold them in place but I don't know that they really did a whole lot in the end. In all reality it didn't really matter which ones I used because they did both work and if you close the top of the tp tubes you can really fill it as high as you want. I would be careful closing the top of the pt tubes though because then you won't be able to attach it to the side for extra security like I show you a little later on.
I taped the top of the rectangle with two vertical strips, half outside the box and half in the tube (this is where the top of your tube rectangle should line up with the top of the box rectangle), to to keep it from sliding down. You also have to tape each side with a vertical strip so the food doesn't fall out. (My chickens thought it was fun to rip a tape side off one day which made a nice mess but was easy enough to fix and they didn't do it again) You can see from the second pic that you can't see the bottom of the tube but in the third pic you can see light under the tube because there is a space for the food to come through.
This is the inside once you have all 6 tubes in. I only had two paper towel tubes so I used two toilet paper tubes as well and just pinched the top shut with a piece of tape so I could still add more food.
I felt the paper towel tubes were a little too wobbly so I guessed about where the top of the tube was from the outside and made a slit then shoved a piece of tape through in folded half into the tube and kept half outside to make them more secure.
This was when it was finished and filled to just below the top of the pt tubes right before I put it in with the girls. I used a large binder clip to keep the top closed.
It didn't take long for them to figure out what it was for, although they did peck at the box itself for a while because its so bright, and then of course how to get on top. I also could never take picture without curious little Pebbles checking out what I was doing.
Overall, this really isn't complicated to make and I had everything laying around the house so it didn't cost anything to make. I used the goldfish cracker carton because of the size and the fact that the inside and outside of the box are coated so it didn't take much to clean it off if they pooped on it. Of course it saved a lot of food which was also great. I used this for almost a month and could have continued to except that I finally got a larger feeder and didn't need it anymore. Since they were bigger they were able to knock it over once it got low so maybe attaching a piece of coroplast or an aluminum pie tin to the bottom to give it some more area would make it less easy for them to do that. Happy Building!
I cut 6 rectangles around the box, alternating 1 door, 2 doors, 1 door, 2 doors because I was worried about the space of the tubes inside and the stability of the box if I cut too much off. Don't cut them too low or it won't keep the food in for you. Sorry I didn't take actual dimensions.
Through trial and error I found I liked the paper towel tube cut in half because even cut in half they are longer than the TP tubes so I could add some more food in the middle of the box. Cut a rectangle a little taller than the door on the box but so the tube is also sitting lower than the opening of the door while not touching the bottom so the food can get under. (sorry about that description) I also cut little notches to try to help hold them in place but I don't know that they really did a whole lot in the end. In all reality it didn't really matter which ones I used because they did both work and if you close the top of the tp tubes you can really fill it as high as you want. I would be careful closing the top of the pt tubes though because then you won't be able to attach it to the side for extra security like I show you a little later on. 
I taped the top of the rectangle with two vertical strips, half outside the box and half in the tube (this is where the top of your tube rectangle should line up with the top of the box rectangle), to to keep it from sliding down. You also have to tape each side with a vertical strip so the food doesn't fall out. (My chickens thought it was fun to rip a tape side off one day which made a nice mess but was easy enough to fix and they didn't do it again) You can see from the second pic that you can't see the bottom of the tube but in the third pic you can see light under the tube because there is a space for the food to come through. 
This is the inside once you have all 6 tubes in. I only had two paper towel tubes so I used two toilet paper tubes as well and just pinched the top shut with a piece of tape so I could still add more food. 
I felt the paper towel tubes were a little too wobbly so I guessed about where the top of the tube was from the outside and made a slit then shoved a piece of tape through in folded half into the tube and kept half outside to make them more secure.
This was when it was finished and filled to just below the top of the pt tubes right before I put it in with the girls. I used a large binder clip to keep the top closed. 
It didn't take long for them to figure out what it was for, although they did peck at the box itself for a while because its so bright, and then of course how to get on top. I also could never take picture without curious little Pebbles checking out what I was doing. Overall, this really isn't complicated to make and I had everything laying around the house so it didn't cost anything to make. I used the goldfish cracker carton because of the size and the fact that the inside and outside of the box are coated so it didn't take much to clean it off if they pooped on it. Of course it saved a lot of food which was also great. I used this for almost a month and could have continued to except that I finally got a larger feeder and didn't need it anymore. Since they were bigger they were able to knock it over once it got low so maybe attaching a piece of coroplast or an aluminum pie tin to the bottom to give it some more area would make it less easy for them to do that. Happy Building!
