My family recently got a batch of chickens, we got 3 Silkies (6 weeks), 2 Ameraucanas, and the guy said he would give us one free Polish top-hat. The Silkies and the top-hat were already in the same cage and we didn't see any issues with the bird.
Over the past week or so we have notices some things. The top-hat is always sleepy, he is very weak, and doesn't run away like the others when trying to be picked up, and recently has a swelled eye. He is also not growing like the others. This is our first batch of chickens that we are raising and we weren't prepared. We later separated the chickens into two pens to give them more space. Silkies in one, and the younger Ameraucanas with the top-hat. When we first got them, the Ameraucanas were smaller than the Top-hat and now they are larger so he isn't growing as fast or at all.
Ages of chickens (now)
Silkies (3)- 8 weeks
Top-hat(1)- 8 weeks
Ameraucanas (2) 4 weeks
