Added button to bird form to bring up a graph showing the productivity for a female.
Click on this to bring up the productivity graph.
This shows you, for each year of egg production, the number of eggs Laid, Fertile, Pipped and Hatched.
If you hover your mouse over one of the columns a tooltip will come highlighting the details of that column.
You can keep the form open, move back to the bird form, select another bird, then click on the graph form and it will update the data to the bird you are now on.
Clicking on the print button on the toolbar will bring up a print preview of the graph allowing your to print it, or save as PDF etc.
Added code that checks that a microchip entry is of the correct length either 9, 10 or 15 digits long.