There are probably as many different ideas for nest boxes among keepers of Bengalese as there are varieties of the bird.
I have seen Bengalese breeding in every type of site from plastic baths, canary nest pans, wicker basket's etc., but with what sort of success.
When it comes to our aim of producing youngsters from our birds this item of cage furniture needs more thought in its placing and design than anything else, it is the centre of our bird's world sometimes for the best part of 6 months of the year. So the more trouble free we can make it the more acceptable to ourselves and our charges it becomes.
The ideal material for box construction is wood, and most boxes are made from this material, the alternative is cardboard, and you can either construct them yourself or buy either type readymade.
For siting your boxes you have the alternative of inside the cage or outside.
For boxes hung outside I think wood is the best material to use, mine are constructed of 6mm ply.
I have seen some very good and practicable cardboard boxes used inside the cage, and if you must hang your boxes inside, they are probably best, due to the reduction they bring in weight.
My boxes are hung outside the cage, and my reasons for recommending this are, boxes when hung inside bring a reduction in cage space, also the need for a large cage door that can lead to escapes, and having to remove the box for inspection. The sequence of actions required in inspecting an interior box brings with it an increased possibility of accidents. We bend all our efforts to producing eggs and then chicks and don’t want to lose any through bad box design or placement
The general opinion and advice given about nest box dimensions is that it should comprise of a 5 inch cube. I have tried this and finally settled on a box 5½ inch's square and 6 inch high. Having seen half a dozen full grown chicks plus the parents crammed into the box I found this was the ideal size.
In some places it is recommended that the box has a hole for access, in my opinion I would advise against this, baby Bengalese start looking out of the box at an early age and they will hang out of the box in a line, this is natural behaviour and should be encouraged, something they have to take turns at if the box has a hole for access. Have a full access along the front.
When I construct my boxes I use a liberal amount of strong waterproof glue at all joints to ensure the least amount of cracks and crevices were nasty’s can hide.
A hinged lid at the top of the box giving you access for inspection makes this job so much easier and causes the least amount of disturbance to breeding birds, my boxes are detachable, so that I can remove them and place them on a table when ringing youngsters, saving any accidents such as dropping a chick.
Make sure which ever method you use to attach your boxes they are strongly and firmly attached, it's better to have a bump on your head than a box on the floor.
Where nest building materials are concerned I have tried most things that have been suggested, but find that either meadow hay that is sold in most pet shops for rabbits and guinea pigs or coconut fibre are ideal, usually I start the nest of for the pairs with a good handful of meadow hay and let them finish and line with coconut fibre.
Although a fit pair of Bengalese will attempt to breed in almost any type of nest site, we as their sole providers should ensure we provide the best and safest environment for our birds to reproduce.