personally no I wouldn't, I'm worried that either my horse slips or a driver cant stop/pull over appropriately - its narrow roads around us.
I stick to the arena and wait for days off when I can get to do some off road hacking, I'm really hoping to get to the beach sometime soon
my personal preference would be to just make sure that there is plenty of adlib quality forage, i would perhaps increase the qty's of what he's currently getting rather than adding anything else, or look at an all round feed that incorporates your vits/mins/linseed etc.
what type of horse do you have, what condition is he/she currently in, what is your current management regime? Is the horse out 24/7 or stabled, rugged etc
lots of factors to consider before adding anything extra to feed and how much are you're feeding currently of what you listed?
my mare is quite narrow in front, I find amigo and shires fit her well,
my PBA was very broad in front, big shoulders, Weatherbeeta were the best fit for him.
personally I'd turn out, I wouldn't leave my horse in just for one night to return to being out 24/7 the next evening.
I'm afraid with winter approaching you will need to become used to handling your horse and dealing with field mates in the dark/dusk, be firm and confident, stand your ground...
horse is out 24/7 in summer so my bed is lifted completely once they are out, stable will be brushed down and floor/mats disinfected in the next week or so and lights wiped, white walls painted if I have time.
I always put a fresh shavings bed down for winter.
my mare had plenty SJ experience but not XC so when I took her to her first XC comp she was definitely lacking in confidence, very backward, behind the leg, reluctant to canter, looking at everything.
I spent an autumn cubbing, going pairs xc so she had some support and made sure I took her...
to us the field may look quite bare but its surprising just how much grass they are getting, we just have to look at the length of the grass round the yard verges etc to see that it really is growing even if it doesn't look like it :)
my horse wont touch hay just now, she'll happily eat her...
our stable block is hot and stuffy so they are better outside, we are lucky that there are trees/hedge line round 3 sides so they can find shade, I also bring her up to yard and hose her down to cool her off when I can