It seems you have multiple series with one item in each of them. In addition the items have their XValue set, so that every item appears at its own position along X axis. In this case RadChart allocates enough space for all series in each X axis item i.e. it should be possible to have items from each series in the same X position.
In this case I would suggest using a single DataSeries with LegendDisplayMode
set to LegendDisplayMode.DataPointLabel
. This way the items will appear with different colors (according to the series palette) and there will be a legend item available for every bar.
I have attached a small example with two charts - the first one has several series and reproduces the thin bars (not sure if this matches your scenario exactly) while the second one is populated with the same data source, but there is a single DataSeries.
Hope this helps.
the Telerik team