Plural/singular negative kws

[vanderbolt]

In selecting negative kws, is it necessary to add the plural version of a kw when you have the singular version?

[AdWordsAdvisor]

vanderbolt, it has been so long since I've thought about this question that I want to double-check with the tech folks to see if the answer is still the same - but in my opinion, yes, you'd want to use plurals.

Especially so when the plural may have a different spelling than just the singular with an added 's', such as in this example:

Lets say you have gourmet pet food for every single creature on the planet except for birds. So your negatives might include:

-bird
-birds
-birdy
-birdys
-birdies

AWA

[eWhisper]

Just an FYI -
For verbs, you also want to add the additional extensions:
researching
researched
etc.