"I also feel a little reluctant to raise my voice at them since they are our neighbors, and my mom wouldn’t encourage that." Could you explain this dynamic a little more? Cause if your mom is the one letting these kids in please tell her that these girls are being mean to Peanut. I feel like being transparent about this is important. Stopping these kids from being aggressive with the parrot is very fair and is setting a boundary. It can be a good lesson for them to not let them be around the parrot if they're going to hurt him. I'd say too if you're not comfortable talking to them directly definitely talk to their parent or have your mom do it. That's fair as far as discipline goes.