Incubation and the Brood Patch© Howard Voren. Click here to use this content.
Q: We have recently purchased a pair of sun conures that were supposed to be proven producers. We purchased them sight unseen from a breeder in another state, and they were shipped in. When we unpacked them, we discovered that the female has her entire lower breast area plucked naked. We have heard that females cannot incubate eggs properly iftheir breasts are naked. We have tried to return them, but the woman said that they were only guaranteed to be proven breeders, not in perfect feather. We have no time for incubation or hand feeding from the egg. Is there any sense in even bothering to set up these birds in a breeding flight?
A: Absolutely, positively, yes! In fact, in many types of birds, it is normal for the female to have what is known as a brood patch. This is a naked area at approximately the same spot that you mentioned. In some species of birds, it is permanent. In these cases, it is opened by the hen spreading apart a group of overlapping feather tips that normally cover this area when she is not sitting on eggs. Other types of birds have been known to seasonally pluck out a brood patch when it is needed. This allows the hen to more efficiently transfer her body heat to the eggs.
Of course, this is not a normal occurrence in psittacines. Due to this, the eggs might hatch a day early. This is due to the increase in the overall average incubation temperature that is created by the egg having direct contact with the skin when the hen returns to the nest. When the hen leaves the nest, the eggs cool. When she returns, a brood patch allows her to bring the eggs back up to full incubation temperature at a very rapid rate. If she has no brood patch, the breast feathers between the egg and the breast act as an insulation barrier that slows down the transfer of heat to the egg. The only feathers that assist in maintaining the warmth in an egg are those that encircle the sides of the egg. These keep the heat that is radiated down from the breast and absorbed by the egg from escaping to the sides.
Parrots, not being broad-breasted birds like ducks, accomplish this “encircling effect” with the use of their wings. This is why hen parrots instinctively keep their wings hanging down at their sides when they are properly brooding a clutch of eggs. As long as your hen captures the heat under her breast by drooping her wings, everything should be fine.