Hes not sick, and I dont believe he looks thin. If it was thin or sick, hipbones would show from a combination of parasites and lack of appetite. I dont overfeed crested geckos specifically males due to obesity being a sperm killer in males.
not starting anything but they do look thinner than alot of others I see but Im sure they are healthy if they are in your hands,haven't know you to go half ass on anything.Are you selling them?