Hello Rouen,
MBD is really a symptom of reptiles housed indoors. From what I've read on the disorder, even small amounts of sunlight deter this disease. Did you know that the amount of Vitamin D3 that a reptile can absorb from the sun in 15 minutes, takes 8 hours to absorb from artificial light sources.
As far as the shell shape goes, just like us, no 2 turtles are alike. I personally have never found an adult turtle in perfect condition. Especially the larger species like Snappers and D.B.Terrapins. Missing one or both eyes is common, along with missing claws, whole feet, shell gouges and cracks. But they still survive!
This years count; 1 D.B.T. shell length 13" both eyes gone, the 4 center carapace sections lifted up and alomost detached from the rest of the shell. I have no idea what causes this.
1 Common Snapper, 9" long, right eye gone and 3/4 long crack in the shell between the neck and right front leg.
Common Snapper, 14" long, left front foot cut off at the wrist.
All of these guys were 100 yards or more from the water so I carried them back.
An 8" RES with the same shell lift as that DBT.
Living in the wild is apparently no picnic.
And these are the ones I found alive.
Anyway I'm seriously digressing here. There's always the possibility that the Snapper was a pet at one time which could explain the MBD like symptoms.
Bob, Philadelphia.