probably a dumb question but what is the program or brush that you used for your chicken falin drawing? your art is phenomenal by the way, hope you're having a good day!
Not a dumb question at all! I assume you mean this drawing, right?
The program I use is Clip Studio Paint; as for brushes, I'll just dump all the brushes I use into a folder here.
These are mostly all brushes from the default library or free brushes I found online, but with the pressure and blend settings adjusted to be much more sensitive (my wrist gets tired if I have to press down really hard all the time). Pretty much my number one tip is to mess around with the pressure settings to see what feels better for you - I've never downloaded a brush without modifying those settings.
For the falin sketch, I used the design pencils to do lineart - the "design pencil" for sketching, and the "darker design pencil" for lining. And then the light gray fill is just any of the pens that CSP comes with.
For painting, these days I mostly use the "gouache blend" brush, but I've also used the "perfect oil paint" before. The "magda's" brushes are good for filling large areas or getting smoother gradients.
Hopefully that's helpful! Feel free to ask if you've got any more questions.