Hi Lorraine,
I think it’s always best to be cautious, so I agree with your choice of what to give your birds. In light of the pandemic in particular, distribution warehouses are disinfecting shipments. Whether the residue can still be toxic by the time it makes its way to you is hard to know. But companies have always sprayed insect and rodent repellents on boxes and papers under certain circumstances. When newspaper was commonly used in bird cages, owners were always warned not to use newspapers from a machine because those were sprayed with chemicals. You also do not know what else was shipped or stored with other boxes, so they could have absorbed something toxic from other boxes.
One of the most compelling reasons not to provide boxes to pet birds is that a box can be a hormonal trigger. Any type of excessive shredding can be a hormonal trigger. If you have female birds, it’s best to avoid boxes and shredding materials entirely, to prevent the triggers and out of concern that she could become a chronic egg layer. With male and female birds, a box can cause territorial aggression. There are so many wonderful bird toys available these days, there is no need to offer boxes if the risks are greater than the benefits. Smaller food boxes are generally OK, unless you have a small bird that wants to get inside of them.
Thank you for asking Lafeber,
Brenda