Tonight we tried an experiment.
Method: We added about 1 Tbsp of ground chia seed to 1/2 pound of ground turkey. From this we made 2 turkey burgers (on the yellow plate).
We also made a couple of "controls": these burgers were made without chia and are pictured on the white plate.
Results: We could taste the chia seed, in the burgers, but it wasn't unpleasant. The burger also didn't shrink as much and seemed moister and more uniform.
Conclusions: This leads us to wonder if the chia seed held onto some of moisture that normally drains out of burgers as they grill. The next time we try this, we'll weigh both burgers before and after.