How to color wood:It is possible to use regular, unsweetened Kool-Aid® to dye wood. Using Kool-Aid® as a colorant results in lightly, almost pastel colored wood. It is usually easiest to use a large, shallow pan which allows for soaking of the wood. Make sure to use no more than half the recommended water amount per package of Kool Aid. The less water you use, the stronger the color.
If you are looking for darker, bolder colors, use commerical food-grade food coloring. It is usually possible to buy bulk food colorings at a food supply outlet or cake decorating shop at reasonable prices. It is a good idea to wear plastic gloves when doing this so that your hands do not get dyed, and have a pile of throwaway rags or alot of paper towels available to set the wet dyed wood down on. (It will get dyed too).
Yet another way to dye wood for budgie toys is to use regular food coloring (like you would use to tint cake frosting). After letting the wood dry overnight, soak the dyed wood in white vinegar diluted with water. After some soaking in the vinegar, remove the wood and let it dry. Then rinse it with plain water and let it dry again before using it on any toys.