Another consideration is if this needs to have the fire marshal signed off on it too.
For super budget and not permitted you could get a bunch of washing machines and a team of people dunking 2lbs at a time in 5 gal bubble bags in buckets.
I imagine you could do 10k lbs a week like that.
This might not be realistic for how much you have though, I imagine you have around 100k lbs from 50 acres right?
Then you could get a bunch of 50l rotos like this one, this model is only $4450 plus shipping.
For the chillers two of these window acs converted to chillers using large coolers and 50/50 auto antifreeze/distilled water with eco plus submersible pump would work for a dual coil 50l roto. I just use one with my 20l roto.