Here is an excellent video from Dr. John Lamberton, in this video he explains how his loft is designed. His loft is setup like most belgian lofts with multiple identical sections and each section has 6, 8 or even 9 nestboxes and each nestbox is identical. A great tip as you will see in the video is only use the nestboxes for the amount of birds you are racing, don’t fill each nestbox just because theres room. When you do it that way each hen will have plenty of room and will not be overcrowded.
When designing your loft make sure that you divide it into small sections that you can control and make sure that each pigeon has plenty of room.
*Video* Loft Design, Dr. John Lamberton by Dr. John Lamberton