u/Full-Yesterday-526

Hello, I recently got a bunch of tuliptree silkmoth eggs because their mother decided to lay them in my house. I wanted to raise them to ensure they all survive so I put the eggs in a small plastic cup with air holes. They hatched today so I put fresh yellow poplar (tuliptree) leaves that were newly grown so that they'd be soft and easy to eat in their container and all day they've just been huddled up on the top of the lid and I haven't seen them on or eating any leaves. Is this normal, is there anything I can do to get them to eat? I don't want them to starve or eat each other.