The answer is twofold: Price & Time.
The price has always been a bit expensive, but in recent months it has become astronomically expensive. At the time of writing, to ship a single pair of ears in my 4" box that weighs less than a pound to Canada would cost me north of $34 USD, and north of $55 for the UK. Seeing as that price is half or even more than the value of the ears themselves, I cannot be comfortable asking someone to pay double for anything I sell.
Time is the other factor that has always plagued international shipping. The act of shipping itself takes longer by filling out forms, ensuring they're given to the right people, tracking the package, eventually having to explain to the customer how packages get stuck in customs/don't move/say they were delivered only to show up 9 days later. Not to mention any of the time it takes to look into taxes and how to minimize what the customer pays when they get their package. And this all assumes the package gets delivered when more and more packages in the USA are magically disappearing. All of the above takes time. And I don't begrudge the customer for asking questions or being worried, but it leads to more communication, pointless phone calls, and worry that takes up a lot of time. This is not my only job, it's technically my fourth job. If it was my only job, I would find a way to ship internationally. But sadly, I don't have the time or the mental bandwidth to figure it all out.
I'm very sorry if you're left feeling put out. I don't want anyone to feel like I'm doing this directly to them. It just doesn't make sense to ship internationally in our current climate. I will check back on the prices every few months as I normally do. But as of this moment, I cannot offer international shipping. I am very sorry.