I like the Zieis brand bird scales, very accurate, good price, and a 10 year NEW replacement warranty, if it fails they replace it with a brand new scale
Haven't looked at the other scales, but you can weigh your bird and his/her food on the Zieis scales,( perch for the birds, platform for everything else) will even zero out the weight of the container used to hold the food,(no need for a second scale), many also operate on battery power as well as AC power for portable operation and have auto shut off after a minute to save on power