Vaseline......!!! That should do it, a very simple solution. Brilliant...thanks
As for covering the IBC's themselves I'm looking into waterproof insulating materials and seeing if I could knock something together on my sewing machine - a big cover or something.
We are also considering tacking carpets onto the tin sow arcs but are a bit unsure about it. If the carpets get wet, they will surely just hold the cold (?). Are we best of keeping these as flappy doors and making sure the arks are stuffed with straw.
I guess there is no simple solution unfortunately. Just hard work.
Chatting to some old pig guys that had an indoor unit, they told me how much trouble they had with an underground piping system. In cold winters it would freeze and stay solid so there job, for days on end, was just to literally keep hauling buckets of water around in the unit. Literally all day. Water was critical to weigh gain, and at very worst, lack of water kicked off salt poisoning.