No the usual ‘argument’ that references is that it you have a complaint or preference or comment or whatever about your work or job duties, you have to bring it to your union rep, rather than talk directly with your employers management. Somehow that’s supposed to be an argument against unions.
You can also feed them less, and then put that kibble in the treats as part of dinner time. So they’d get half their dinner from the bowl and half from a puzzle toy, or whatever.