No. It sounds like they are just hungry for them, and their usage will level out once their need is satisfied. Mine do that too when I fail to notice that their feeder is empty for a few days. I've started running the girls into another pen and only letting in a few at a time so their isn't such a mob when I refill feeders.
This is what I use to feed mineral. I mount it with screws on a board or railroad tie under their sheds. 2 girls can access the mineral at a time, and it's pretty durable unless they can knock it off the screws.
Depends upon salt % but you should ease them into it if its their first time. For the first week bring out some pans and let them have at em for a minute or so and then take them away. If its a mineral with high salt you can make their blood pressure jump up to much.
They will settle down with it after a few days. I would do like sweetgoats suggested and put a few areas of it out to allow them all access at first. If you just have one mineral feeder just put a little dab in a few feed bowls so they can spread out for the initial indulgence.
I agree about easing them into it. I put out multiple feeders for mine spaced a good distance apart so everyone can have some without a fight. If mine don't eat it all then I change it out every other day to keep it fresh. I have found that the plastic mineral feeders like this http://www.tractorsupply.com/en/sto...l-feeder-2x175-qt-capacity-black?cm_vc=-10005 come in pretty handy. I use to use the plastic over the fence feeders but this style lets me put kelp on one side and minerals on the other. Then I place another one with baking soda and minerals in another spot and so on. I put zip ties through the holes in the feeder and then use little snaps to place them either in the shed or on the fence depending on the weather. Once you build them up to be use to it then you can leave some out free choice.