Delegate-at-large is a hyphenated compound noun.
When attempting to pluralise such words it is important to identify that part of the compound that is subject to the change in number and add the plural inflection (-s) to that element.
Delegate-at-large is a special type of delegate, therefore delegate is subject to the plural inflection, so the plural of delegate-at-large is delegates-at-large.
The plural way to spell studio is studios.
The plural is cantaloupes.
The plural is roses.
The plural is "emeralds."
The plural is "recesses".
The plural way to spell studio is studios.
The plural is resources.
The plural is cantaloupes.
The plural is roses.
The plural is "emeralds."
The plural is cherries.
The plural is hooves.
The plural is bridges.
The plural of "instrument" is spelled "instruments."
The plural of "race" is "races."
The plural is a normal S plural, associates.
Trout is plural