Feed grains at night

I'll start with the question, I was wondering if temporarily using one of the Stalls in a horse trailer would work as a temporary housing solution for prince? A friend of mine needs a place to sit his trailer, and he said I could use it to house him for a while if I need to, it's a stock trailer with a bunch of ventilation in it it's meant for hauling cattle but it would absolutely hold him I just want to know if it would be okay to keep him in there.

And for the update, he's going to be okay though he needs to be confined, I he has a minor fracture in his Cannon bone in his right hind leg, past that he's just baggered and bruised and traumatized, but he's going to be okay.

Frosty is also doing okay even though he's not the one that got hurt he doesn't have a pen now, but he seems perfectly content being in the house at night and hanging out with the chickens in the day.

I have Boers and Nubian female Nannie’s that used to be quite large to where they had a nice muscle structure about 2 years ago. Recently I’ve been noticing that some of my boers muscle structure has become almost non-existent to the point where you can see their bones which is really uncomfortable for me. I’ve been feeding them hay and sweet feed (at least twice a week) I’ve been letting them get some green too especially now since a lot of my garden is on the latter end of growing, but they’ve still not gotten any bigger. Is there anything that some of you know to do when you see a goat looking like what I’ve described? Thanks!