peepers...do they fit on all chickens?

[Kendallou]

Help! I have some horrible feather picking chickens! They are New Hampshire Reds. I have purchased some of the pinless peepers and I am having a hard time getting them on. Does anyone have experience putting them on New Hampshires?

Would it be better to just clip their beaks? I have had some older folks telling me to do that. But will that stop the picking? Or just keep them from injuring one another?

Thanks!