How Big are they?
What have you tried feeding them?

I had a large male collard lizard (wild caught) that would eat spiders & crickets for about a month then wouldn't eat for about a week then spiders & crickets for about a month and again wouldn't eat for about a week one day during the no eating period I dropped in couple side bloched lizards instant feeding responce and continued eating spiders & crickets. After that one side bloched every week or two never stopped eating after that.
Had him about 11 years.