I'll let you into a secret here - Eddie hates tennis balls :o However he loves food and bouncing around everywhere With flyball, being ball mad does help, but it isn't the be all and end all - after all if you have a dog that is ball mad, you can come across a few problems - they may turn around when they hear the box being reloaded for the next dog, they may not give the ball back to you etc.
To start off with in training, we do runbacks, where they just run out of the lanes over 1 jump, 2 jump, 3 jump, 4 jumps and get heavily rewarded for it. Then they go into the box area, if they have some mild interest in a ball, and can fetch, then that's all that matters. You tell him to fetch and the boxloader rolls the ball down the box - the movement is usually enough to get them to notice it and get it in their mouth. Heaps and heaps of praise is given, and they realise that it is a good thing to go near the box and fetch a ball. Over time they forget the ball and just do it anyway. Eddie spits the ball out as soon as he gets back to me and is more interested in the tasty sausage he's being fed than the ball he's just given me
As long as Ash will fetch a ball, the rest can be trained into them. Shara's also dog aggressive, but at training she ran in a team of other dogs for the first time last week