Feeding help for rabbit

Hi
I have a 2 year old rabbit. She's a mixed breed that we got from the shelter, and I have some questions about her diet.

My family is going away for the holidays. We bought her a gravity feeder that gives her a constant supply of food. I'm not sure if that's healthy. I normally give her half a cup of pellets a day. Also, she won't eat Timothy Hay. I've been told that it's essential, but she's done fine for a little over a year.

Should I try giving her Timothy Hay again?

Thanks for any help