Also, as you dont know exactly (without assuming) his breed/s, you can really present him how you'd think he'd look best.
Showing in Unreg, i've seen many not plaited.
I will get the kids pony (Pt Welsh but again unreg) out inhand soon, i wont plait her but she's clipped. Cant plait as she has a "broken crest" & the plaits just look stupid.
