Stijn: your hypothesis about mineral deficiencies is interesting. I have used Miner-All I for long, it has a very complete range of minerals though. ...
baby cresties eat very tiny amounts. you can't always see the evidence. is he in CK on paper towels or something similar? as long as tiny poops show...
mine all do, but then I only have a trio and a handful that I bred in '11. maybe he didn't eat it because he's nervous, too? you'll have to update us...