WOW! I did not realize that an adult male could go into a 28 quart tub. I thought if I put him in something bigger he would go off his feed. I am glad i asked you this Deborah. My guy is in a 16 quart right now but he is just over a year old. So its ok to move him into a 28 quart now!
I will tell you just like I will tell you someone with a BP see how it goes, usually it will go fine (reason I love V35S vs 28 qts is their very low ceiling). Male hogs are bound to go off feed either way and keeping a smaller tub can become handy when they do.