If once a day is all you can do, increase to 20 mg/kg.
Example for 1 pound:
1 / 2.2 x 20 / 100 = 0.09 ml once a day
Note that the example is for one pound now, not five.
If it's 10% enrofloxacin, you need to weigh each bird and give it orally based on their weigh.
Give 0.07 ml per pound of body weight twice a day for 3-5 days. If they don't respond after 3 days, stop giving it and look into getting something else.
The dose I recommend is 15 mg/kg twice a day...
Baytril = enrofloxacin
Tylan 50 needs to be given orally.
Give 0.33 ml per pound of body weight orally three times a day.
Tylan 50 is labeled/approved for cattle, so there are no directions for treating chickens.
When given by injection, it can cause severe injection site necrosis, so...