I am in the process of building an indoor outdoor enclosure (using my back porch and a section of yard) i was wondering if it is imperative to have a lid on the outside part. Hercules is an 8 yr old Sulcata weighing more than thirty pounds and will be brought in at night and if I am not home. I don't think a hawk could pick him up and him sleeping inside means we wont have to worry about nighttime creatures. Is there any other reason I would need to put a lid on?