Hannah, re Gerty.Independant tests were done on this mix and the colourants were found to cause renal problems in some pigs. I used to use this mix and I did seem to get a high concentration of pigs with cystitis.I changed the mix about 5 years ago and the cystitis level has dropped right off.,in fact over the last 4 years I honestly have not had one case of cystitis.I rang the Gerty help line a few years back and spoke to the nutrionist there.She admitted that the colourants were only addded as a selling point.She reckoned owners would go for something bright.I discussed the renal problem with her and she did agree that because colourants can cause problems in humans they could possibly do so in pigs.I was told that they were thinking of making an additional ,plainer mix with no colours,but I have watched the market and have never seen any new mix.,but maybe someone else has?.Having said all this,I have some friends who use Gerty for their pigs who live to 7 and 8 years and they do not get a cystitis problem.Then again a friend of mine with 2 sows fed on Gerty had cystitis on and off very frequently.After being taken off Gerty ,the cystitis stopped.This like most things piggy is very controversial--maybe some pigs are just more sensitive to the chemicals.Bottom line of course is if the dry mix you use is liked and the piggies are thriving,why change.? Mary