We’ve a 10yr old one here afraid of his own shadow when it comes to bangs or loud hisses(air brakes) but loves to run down barking and angle grinders chainsaws welders etc..
He is not the worst he likes to pick and choose his spots, as for the mobile barriers that's just what they are I use them for directing cattle around the yard,got sick of using white tape so I went overboard and got them made up 4 in total so when put together they stretch from cow shed to calving house ,total control over cattle with them. I have pins to hold them together.It must be a nightmare to keep a hairy dog like that clean as you have it , in a farmyard environment.
I also like your mobile barriers.
Would an odd one stick their neck out through it , and move it ?
Also , just out of curiosity, what make is the mast shear grab ?