Weekend make-a-long: Colouring Eggs

Well as an instructional make-a-long this has already gone wrong.  I was trying to colour eggs and I failed so this now is a plea for help...can you tell me how to do it.
Inga is one of my students and she is from Latvia.  She said she was colouring eggs for the weekend and I asked her how to to it. So Inga uses lots of onion skins, she puts them into a pot with water and hard boils eggs in.  The onion skins colour the eggs a deep brown. She also said that she ties leaves onto some of the eggs and this leaves a leaf pattern.  Another design is made by putting an egg into a pair of tights and surrounded by raw rice. This gives a stippled pattern on the egg.
I decided to try this out this morning and patiently waited on the hens to lay.  I collected the eggs and then discovered I had no onions left (busy week making lots of curry used them all).  I did find loads of food colouring and decided blue eggs would be nice and heaped the food colouring into the pot, and boiled, and boiled, and boiled.  But no luck, I was expecting deep blue eggs but they are still the colour they started. One of them cracked and when I shelled it discovered lots of blue veins around it, weird looking more than pretty.  I haven't shelled the rest yet.  I did end up with some fantastic deep blue rice cooked though. 
I'm a bit wary of trying again afraid to waste more eggs.  I do think though that I will feed the blue rice to the hens and see if that affects the colour of the shells.
So, instead of me teaching you how to colour eggs I am asking you to teach me...thanks.