They will loose about 50% of their feathers and look rough for 2-3 weeks. Stopped laying until they got their feathers back, and started back slowly laying. Overall time frame about 4-5 weeks. My molt came late winter, but they had been under lights.
Dont be surprised if they quit after a week of laying, and go 1-3 weeks before they start back. Mine have always started then stopped and then restarted. Also never had any start at 21 weeks, but either way you will love these birds.
Most of mine start laying from 26 - 28 weeks of age. Sometimes they will start 24 - 25 weeks but then they will stop after 4 - 6 days of laying for 1 - 2 weeks then start back consistent. The group of roos that I am raising for meat are only 12 weeks old and I plan to take them to 18 - 20 weeks...
Out of 5 hens, I have one that lays a normal size egg, 4 that lay a jumbo egg, and 3 pullets have started laying and their eggs are getting bigger each week.
Finally got a digital scale today to weigh eggs. Collected 4 Bielefelder eggs today the smallest weighed 2.68 oz. and the largest weighed 2.96 oz.. My hens turn 2 years old in another month and have experienced no prolapse or other egg laying problems.
In response to the comments about Bielefelders being feed hogs, I just finished a 21 day track of 22% mini pellet feed. There are 2 groups, group A consist of 5 hens and 1 roo all being 23 months old and laying 4-5 eggs per day. Group B consist of 5 pullets and 1 roo all being 23-27 weeks old...
At what age would you put a young roo in with 3-4 older hens? What would signal that he is of breeding age? The Biel pullets take longer to mature, so I am wondering if the roos do too.
Personally, I would use a short solid wall on the bottom (24"-36") and then wire on the upper portion of the wall. Heat will rise and go out while still offering the most protection. And I agree a box fan works wonders......