Tylan shouldnt be given for 3 weeks. Tylan injectable is only given for 3-5 days depending if it's injected or given orally. Tylan soluable is mixed in water and should only be given no more than 7 days maximum. Anything greater than these time periods is a waste of time and ineffective because...
Chickens dont get colds. They get a specific disease. Respiratory diseases are easily spread to other birds, are transmitted on clothing, shoes, your hands, vehicle tires etc...
Antibiotics such as tylan, gallimycin, duramycin and all antibiotics simply mask symptoms and dont cure the disease...
Yes, it tells me a lot. It tells me that his birds have respiratory disease(s.) That's what gallimycin and tylan are used for. It also tells me that his show birds were probably infected at bird shows and if he continues showing his sick birds, his birds will be spreading the disease(s) to other...
Why are you mixing two antibiotics together and giving them to your chickens? Mixing two antibiotics together changes the chemical properties in the medications which could possibly cause adverse reactions, possible organ damage or worse...aka contraindications. You must give one or the other...