Has any one ever used one of them firepaw slat mills or carpet mills they have them on amazon there not cheap but would do good for the nights when its pissing down and if u have room in the shed you could use terriers or smallish running dogs on them aswell
Firepaw Dog Carpet Mill/Treadmill / Training/Stamina https://www.amazon.co.uk/dp/B07BWD2724/ref=cm_sw_r_cp_apa_i_aedfCbFEP12J9