Yes there are butlers around that get as big as you have heard.... Yes they are rare and most that you see for sale just are not up to par. Even in the best lines most will top out at 14 oz or so at 24-26 weeks..... I didnt usually butcher them till 30-36 weeks... This was to allow the ones that were going to be huge, stand out..... if you butcher butlers at 24 weeks, they will all be 14 oz or so birds.... you just cant tell which ones can be huge till they have a chance to well.... get huge! Its slow and feed cost or your time cant be a factor you care about. Butlers simply grow too slow for this mind set....These are truly a bird for "Bob freaks"....someone who just loves bobs.... A adult hen of good stock will throw eggs in the 15-16 gram range on average.... laying season is what any other bob is, cant change that much without a trade off of fertility or lifespan.... Overall condition of hens will drop and winter will be harder on them.
You seem to be interested in eating big bobs quick and getting lots of nice eggs. I agree with you on the taste of Bobs over cots. Dont think this can be argued by anyone who has eaten both side by side.... Cots just suck beside a bob on the the table...
If you are looking for great on the table, big birds quick, nice eggs and long laying season, Think about chukar.... They lay longer and lay bigger eggs, about 20-22 grams on average.... They hatch easy and can be colony raised in any growout pens that work for bobs...Same for breeders, trios usually work, same pens as you'd use for bobs.... ready to butcher at 16 weeks. Hens will run 20 oz and cock birds will be 21-22 oz.... I have cooked them in the same skillet as bobs and with exception of the size, you cant tell the difference in taste..... I raise them as my game bird "meat bird" and put 50 to 100 in the freezer every year..... They are pretty, out of the ordinary, and make a range of awesome sounds.....
If you truly just dig bobs, I know a breeder that raises nice butlers. He sells a limited amount of eggs and live birds. He no longer posts here and I wont expose him to the emails and questions this site can bring. But I will give you contact info thru PM if you choose to walk this path... But I truly feel simple chukars will better fit your needs.... Bill