My two little DTS both have soft plastrons the carapace is very hard. I dont know if it was soft the whole time i had them because i didnt fuss with them much the first couple weeks my hands went in thier tub just to soak, feed, and clean but now that they are getting comfy i check on them a few times a day and just noticed it. They do have a UVB bulb and go out atleast everyother day if weather is well and also have cuttlebone to munch on. I am going to start putting calcium on thier food. does anyone have any thoughts or advice?