Well, my chicks are only 8 weeks, but they have liked mirrors and some parrot toys that I hang from the brooder cover. The toys I have are sort of chandler style where it has large beads and silver bells and the other one has colored blocks of wood and a bell at the bottom. They love to peck and them and make the bells ring. Some like to sit under it and put there head in the bell like a hat

They also get to run around our kitchen tile floor each day, and we have a few ping pong balls that I marked on. I used orange and black sharpies and added little specks/dots on them and the chicks peck at the ping pong and it makes it roll away a bit. At first they didn’t know what to think, but then they understood and started pecking at it and sort of chasing it as it rolled around. The game only lasts a few seconds before they run of for something else, but someone else comes up and starts to roll it around so it’s at least interesting to them.