If you get layed off it is usually a certain department. As in feeder when its time to lay off they layoff the junior fulltimer (all of your ftime years count package, 22.3 etc). Now you have the right to sit at home and collect un-employment but you do not gain any pension credit in doing so. So usually people just bump the next lower junior ftimer porter, package etc. Now if you dont have enough seniority to do so then you can bump two partimers at your part time rate(total years of service would be calculated) so unless your a pre 1982 hire it would be a pay cut.
Now if its a partimer on the twilight that gets cut, if he/she has more seniority than someone else on another shift they can exercise their seniority and bump that junior employee.
If layoffs do happen, you must not turn a blind eye to supervisors working. Why should they be allowed to do our work when we have layoffs? This is one way of insuring the layoffs wont be long, but if you allow the company to work you might be displaced for some time.
We are in our heavy vacation schedule right now, easter thru labor day so i cant see how they plan to layoff. Jan thru now is when it usually happens but not typically the spring and summer months.