(Ponies are much happier if they have a companion so it is best to have two if possible). Cost of keeping a couple of ponies. The cost to keep a couple of miniature Shetland ponies per week is as follows:- If not on good grass then one miniature pony would eat just one or two bales of hay per week at £2 - £4 per bale. The ponies would need to have their feet clipped three or four times a year which costs about £10 - £15 each time.