In my refrigerator today I found a package of commercially prepared shredded hashbrowns that was 2 weeks past the “fresh by” date. The package was swollen up like a balloon so I threw it out. Could the package have contained botulism?

You did the right thing by throwing the package out. Any time a can is swollen or a refrigerated plastic pack balloons in size, it is prudent to discard it. If the package had been stored improperly before you bought it, such as being stored at too warm a temperature, this may cause the potatoes to break down. There is an excellent section of common questions about potatoes that discusses this specific issue.