Instead of the chicken wire use a pipe. Cut slots in the top of the ends and you can lift the pipe off to load the trough. With the pipe free to spin they won't be able to perch on it, especially a small diameter pipe. The height of the pipe should be around two inches above the edge. The smaller ones may try to stand in it but they will be uncomfortable and soon stop, especially as they grow.
This is mine. I made it out of a piece of vinyl gutter. I just used what we had on hand for the legs and the ends. I used a piece of metal the length of it to help hold up the poultry wire because I knew they would want to GET ON IT. lol Going to make one more out of the other piece of gutter. Only thing is, it's hard for me to spoon the food in it with the poultry wire over the top but IF I didn't do that they would be standing in their food!
I had it attached to the wall BUT they couldn't feed but from one side of it and I have 38 chicks ranging from about 8 weeks old to 6 week olds.