ive been looking in to useing them theres a sunday tuesday and thursday tea all do diferent things theres a link to his site on www.topracingpigeons.co.uk
i would say the same thing duramitex on the felts would be leathel breathing in that all day not good i can not even stand it on my fingers must do some damage to the respiretory system.
5 days is when you should put the rings on if the chick looks to have small feet leave it a day or two i start to have trouble getting mine on after 7 days.