Jos Thoné was probably the first to introduce removable box-dividers for young birds and hens.
These removable box-dividers are very simple yet serve an important function:
1) larger space: more birds can rest in smaller loft
2) easy to handle: pigeons will be calmer and easier to handle
3) tameness: birds will become tame faster
4) removable: to create 'couples-box' for e.g. motivation or breeding