Yes.
150pounds
They watch what they eat / drink, and get plenty of exercise.
they don't have to be they are normally because less weight makes them go faster
The Clerk of Scales is the official (under the Racing Secretary's Office) who "runs" the Jockeys Room, weighing the jockeys out before a race and reporting any discrepancies in their weight to the stewards. His job is to make certain the jockeys are at or under the legal weight for that race's (and their mount's) allowance. The Clerk of Scales also notes and reports any changes of jockeys or of silks, and provides the Paymaster of Purses with a list of riding fees due each jockey that day. This is also the official who can be seen in the Winner's Circle after the race, recording the weight of every rider (and his gear) after he or she dismounts, to make certain no "weight was dropped" after the jockey's pre-race weigh-in.
Jockeys need to be small because that means that they are light weighted. They need to be light weighted so the horse doesn't have a lot of weight to take on. This makes the horse be able to run as fast as it can with being in control.
There is no king of disc jockeys.
Jockeys' Guild was created in 1940.
The ISBN of The Rock Jockeys is 0440410266.
Airchecks are typically a requirement for broadcast disc jockeys made by the stations for which disc jockeys work. Some disc jockeys choose to do airchecks on their own but it is uncommon.
The Rock Jockeys has 80 pages.
Because then they wouldn't be CAMEL jockeys, they would be HORSE jockeys. And there is a huge difference between the two.