Mine are breeder quality - they never start laying before 24 weeks. Most are in the 24-30 week range, though I did have to wait 11 months for one stubborn pullet to start laying.
They are not known to be a broody breed. And they are supposed to be terrible sitters and mothers. Now with that said, I have had 2 of my welsummers go broody this year. The first went broody last year as well - she is a good sitter and a fantastic mother. She is still mothering her "babies" even though they are about 11 weeks old. The 2nd welsummer pullet (she's only 7 months old when she decided to go broody) just hatched out her babies yesterday. She is very protective of them, so hopefully she will do well as a mother.