I wonder if this chick would eventually grow skin over the top of that knot? Here's some info found:
Deformities
In any animal population during embryonic development, there is a predictable incidence of embryos that die or are not able to hatch due to deformities. Based on this comprehensive investigation, data demonstrated that the percent of deformed embryos ranged from 0.22 to 0.30% of the total hatch. These findings suggest that hatchability declines on the average of 0.25% due to malformed chicks. A combination of deformities and malpositions can be manifested simultaneously. Table 2 shows the incidence of common deformities observed from embryos at 15 to 21 days of incubation. The most common deformities are those of exposed brain (29%), without eye(s) (25%) and with beak abnormalities (+/-35%). http://edis.ifas.ufl.edu/vm095
Deformities
In any animal population during embryonic development, there is a predictable incidence of embryos that die or are not able to hatch due to deformities. Based on this comprehensive investigation, data demonstrated that the percent of deformed embryos ranged from 0.22 to 0.30% of the total hatch. These findings suggest that hatchability declines on the average of 0.25% due to malformed chicks. A combination of deformities and malpositions can be manifested simultaneously. Table 2 shows the incidence of common deformities observed from embryos at 15 to 21 days of incubation. The most common deformities are those of exposed brain (29%), without eye(s) (25%) and with beak abnormalities (+/-35%). http://edis.ifas.ufl.edu/vm095