Aren't the Vorwerks in the US banties??? I would expect the egs to be smaller then but pulet eggs are often smaller when they first start laying...so they may get a little bigger over time. Also they are more dual puros type chickens as far as I know and I don'tthink they'll lay an egg every day. When starting out it may be even more irregular... As far as incubating the first egg - I would assume that it could be incubated if the rooster is doing his roosterly duty but I don't know if the hatch rate in first eggs is any good??? She is pretty, hope you can get some offspring from your little Vorwerk flock
And just my little bit of Vorwek 'knowledge (yea, right....) I think they are a german breed from like late 1800 or early 1900 and were standards size there and they have Lakenvelder and I think Buff Orps and then something else crossed. Later in the US someone came up with the banties??)