DERBY favourite Deerfield was evacuated yesterday from trainer Alex Wong Yu-on's stable where 10 horses are on the sick list. The budding champion was transferred to a box in the stable of neighbouring trainer Peter Ng Bik-kuen. The precautionary move was another chapter in Deerfield's traumatic preparation for the $3.5 million Derby on March 7 which looks like continuing right up to the eve of the Classic. For, after suffering two bouts of the virus and having quickly recovered from a mysterious back complaint, he now has a minor hoof problem and trainer Wong is awaiting veterinary permission for the horse to race in the Derby wearing a specially imported aluminim shoe. The American-bred four-year-old has developed a quarter crack in his heel and Wong is seeking the special Australian aluminium bar plate to give the heel support. ''It's the first time such a plate has been brought here although it is common in Australia. I have to show it to the vet and get approval to fit it on the horse. ''The small crack is not bad but you don't want to take any chances and fitting him with this bar shoe would be a definite help. At the moment we are also restricting him to slow pacework but he is fit enough anyway,'' said Wong. ''We are facing some minor problems but I am confident that we will get him to the race in great shape.'' Wong has had a tough season and 10 of his string are now out of action but the trainer and senior vet Keith Watkins both stressed the horses were not badly affected. Said Watkins: ''I would describe them as being 'off colour'. It might easily be like human beings who suffer from post-viral depression. Some recover quickly and others feel pretty low for some time. ''Some of these horses are running low-grade temperatures, others are off their food, some are slightly constipated and others are a bit loose. ''We are taking blood samples, of course, to get them checked but they are all on a self-recovery programme,'' said Watkins. ''Clinically, this has nothing to do with the influenza virus but it clearly shows that trainers are really taking a lot of notice now. We are monitoring it all,'' he added. Meanwhile, Irish champion jockey Mick Kinane has declined a ride in the Indian Derby. He was wanted for second favourite Astounding, winner of the Calcutta Derby, but decided against the dash to Bombay on Saturday night. ''Frankly, I just preferred to stay here and get to work on Monday morning. We have runners on Wednesday night and it's better if I'm here,'' he said. English jockey John Lowe, once a winter visitor to Hongkong with former trainer Eric Collingwood, will now ride Astounding.