We have 4 rooms that hold 1000 hogs each on our farm. We have 1 cone bottom bin for each room, each bin holds 18 ton.  Depending on how much ddg's are put in the feed it is hard to guess how much feed is in each bin when looking down from the top ( because it tends to bridge up with higher levels of ddg's).  There are times when we run out of feed on weekends or holidays and have to pail feed to 1000 hungry pigs because I guessed wrong on how much feed is in the bin. My goal would be to be able to track feed usage for that particualar week and then determine whether I will make it through a weekend or holiday.
My question is; has anyone ever put scales on feed bins like mine ? 
Do they hold up in the harsh weather conditions we have in midwest ? 
Are they expensive ?   

TIA !!!