I happen to think building a bator is an excellent project because it involves electricity, science, working with tools and more. It would be a great project for right now. Hatching eggs could be a great project for another time after you and mom have talked about and agreed upon what to do with chicks. It extreemly satisfying to hatch chicks. Another aspect of 4h that people sometimes forget about is the emphasis on agri-business. If you can take the time to work on a simple business plan look ahead to hatching out eggs for next spring and you will likely be able to sell them and make a little money to recover your initial expenses. So, here's my suggestion: talk to your 4-h advisor about the poster project and see if it would be enough. Combine the poster project with a business plan of how much it will cost to build and how many sales you could have in the future. Build the bator. Wait patiently for mom to say yes because eventually she will. Prove to mom that you are a mature thinker by having a good plan (and that includes hatching out birds that you will be able to sell) and not being impatient.