Question about heated pet bowls

I have a plastic heated pet bowl similar to this: http://www.tractorsupply.com/tsc/produc … _vc=-10005
I was wondering if I could fill it with sand instead of water so that my hens have a place to dust bathe inside the coop on days when it's really cold and windy - like today. It was -30 C, with winds gusting to 38 km/h from the NW at 7:00 a.m.
Does the pet bowl have to contain water? Will the plastic melt if I fill it with a non-liquid?
The bag of sand I have is stored outside and is rock solid because it's got quite a bit of moisture in it, but I plan to bring it in to thaw if I can use it safely in the pet bowl.

Link not working.

I doubt it's big enough for dust bathing.....but some folks put sand in bowl around a water bowl in those.

Hmm, weird that the link doesn't work - when I enter it in address field in my browser, it brings it up, no problem. Anyway, maybe this one will work: http://www.tscstores.com/125-GALLON-HEATED-PET-DISH-P11305.aspx#.VsSN1bQrJhE

I have a bantam Silkie hen that would have no trouble taking a bath in it, but you are right - my LF Speckled Sussex would probably not have enough room.

Thanks for letting me know that some folks do put sand around a water bowl - this means that I can (safely, I hope) use a non-liquid in the heated bowl. This is good news to me because my other idea for this heated dish is to use it out in the run to feed the chickens their fermented grains or porridge. With the cold temps we’ve been having they don’t have time to eat everything I put out before it freezes solid, so they can’t get it out of the dishes any more. I’ve had to throw out quite a bit of perfectly good feed the last little while, because FF is only good fresh, not previously frozen. Do you think the dog dish will work for this? Does it matter if the bottom of the bowl isn't nessarily entirely covered?
The reason I'm trying to find a way to re-purpose this heated bowl is because when I was first getting set up for chickens, I bought it when it was on sale, thinking I might be able to use it because I'd read that a number of poultry keepers used them as founts in the winter months. It turned out that it really wasn't a practical solution for our coop/run setup, because the heated dog dish took up too much space inside the coop (it's only 4' x 8'), it had too much potential for spills which would soak the coop bedding making it a breeding area for all kinds of health issues, it was constantly filled with bedding, even when I put it up on bricks, the surface area of exposed water in the dish allowed for more evaporation and higher humidity in the coop, which I definitely didn't want..
I tried using it out in the run, but again, it was messy and high-maintenance out there as well: it was constantly full of stuff kicked in by the chickens scratching about, and when the temperatures went below -15 or so, the dish couldn't keep up, which meant unplugging it and bringing it inside for it to thaw out overnight, then hauling it and the water to fill it back out to the run every morning. Since I don't have a lot of time in the mornings before work, that lasted all of two days, before I gave up on it for awhile.
Now I'm trying to think of other ways to use it because it irritates me that it's nothing more than a big useless $30 dust collector at the moment.

That link worked.......I have one of those collecting dust too, tho it's partially disassembled and highly 'modified'.

Try it and see is what I would do.