The bearding gene is incomplete dominant, so that one copy gives some beard and two copies give more beard. No copies gives no beard. You are correct, it generally means the beard will look fuller. This though can be difficult to tell looking at the individual bearded bird if they have one or two copies of the gene. Because I occasionally hatch chicks that are beardless, this means that I must have some birds that only have one copy of the gene.
Though two of the chicks I thought were Niko’s are actually my bantam Cochin’s. Her eggs were inadvertently placed to hatch. The eggs are much the same size and appearance as some of my Silkie pullets. Her chicks do appear very similar to paint Silkies at hatch until they develop red feathers as they feather in. It’s quite a remarkable difference.
These chicks are starting to develop smooth feathers on their wing tips which is usually evident by 5 to 6 days of age. One of the chicks is beardless and the other one is half bearded. It can also be difficult to tell how much beard a chick will develop as the beard does not come in fully until they are an adult.
Half bearded
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Beardless
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The Cochin mother is beardless so this means my rooster must only carry one copy of the bearding gene, even though he appears full bearded.
This blue chick is full bearded:
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Chick, juvenile and adult photos of half bearded Niko. She appeared full bearded as a chick.
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Full bearded Kana and Laya:
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This Olive Egger juvenile is half Easter Egger and half Barnevelder. She is half bearded.
2 weeks of age:
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At 8 weeks of age her beard seems to have disappeared and only has the muffs left.
The beard may fill in as she gets older.
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Hope this makes sense.