There are so many types of oils! I do like to change the ones I feed my girl and currently I’m feeding 20ml of W3 oil to her as I have it for my ponies right now. And she loves the taste so I use it to paste some of her supplements which she is not a fan of.
But I do like fish oils and have feed herring oil (it does not need to be refrigerated after opening so a bonus) which is about $30 for 1000ml. I have fed salmon oil as well, but it does need to go in the fridge after opening, not a huge deal though.
I have also switched it up with hemp seed oil, and rotate after every 1,000ml. I purchase the 3 above from Big Country Raw as I get 15% off: