I have brown with blue center colony for about 5 years, and light blue for 3 years and a green for about a year and another green one a couple weeks. My colonies don't seem to grow but that's ok with me becuase I like them the way they are. But my green ones are not doing well. My new one had 5 heads and I am now down to 2. My older one loses a head every once and a while and just lost 2 in the past week. What is different about the green ones that make it harder for me to keep?