Move Chunk (assumes) 2.4+

gistfile1.js

function MoveChunk(chunk,count){
        good_shards=["shard4","shard5","shard6","shard7"];
        printjson(chunk);
        moveObject= { moveChunk : chunk.ns, find: chunk.min , to : good_shards[count % good_shards.length], __waitForDelete:false,__secondaryThrottle:true}
        printjson(moveObject);
        printjson("++++++++++++++++++++++");
        printjson(db.adminCommand(moveObject));
        printjson("++++++++++++++++++++++");
}
 
count=0;
db.getSiblingDB('config').chunks.find({ns:"somedb.somecollection",shard:"shard3"}).skip(22).limit(25).forEach( 
        function(chunk)){
                print("->>>>>>>> Processing chunk "+count+"/25 <--------------");
                MoveChunk(chunk,count);
                count+=1;
        }
);