do you need a supershroom to get a better chance of ugly duckling to hatch ?

yes :)

A fully grown Supershroom makes the regular Duckling the same rarity as the Ugly Duckling, giving each a 50:50 chance of hatching from the egg!

Whether you use one will also depend on whether you have more supershroom seeds or fairytale seeds.  If you're short of supershroom seeds, or if you're happy to keep replanting the seeds and getting duckling eggs into nests, you don't need to use a supershroom.

You can still get ordinary ducklings with a supershroom.  Equally, you can still get ugly ducklings without one.

Only have one egg in a nest at a time, and try for twins each time.  It's possible for the twins to be different so you could get either or both from one egg.

It's the one fairytale I didn't use a supershroom for.

I had three lots of twins: 5 ugly and 1 ordinary.  Even when I went back and did a few more, I ended up with 11 uglies and still only one ordinary one.  Still without a supershroom,

And I know that's unusually lucky, but it can be done without the supershroom, if you have the patience to do it  - or if fairytale seeds are more plentiful than supershroom seeds :)

I had zero luck without supershroom....wasted 6 fairytale seeds, ended up putting in SS and got 3 sets twins right of the bat all ugly.  Yes, you can do it without but be prepared to waste a lot of seeds!!

Off not of lol

I didn’t use a supershroom for this one and I had good luck. Then again I also had so many fairy tale seeds it didn’t matter and I wanted to give people chances to spot regular ducklings too. :) I wouldn’t recommend wasting a supershroom but it’s always everyone’s individual choice.

Used a Shroom, got 1 set of  twins despite changing plates constantly, both ordinary chicks. Ran out of shroom seeds and then the Uglies came???