When are chicks "too" crowded

[foreseeme]

I have 25 RIR chicks that are two weeks old. I started them off in 1 "plastic tub brooder" and have spread them out between two boxes. The boxes are about 18" x 36". The photo below is not of my exact chicks, but my brooder is the same design/materials.

The question: Are the chicks too crammed? I have never reaised chickens before, so I have no clue of how crammed is too crammed. When sleeping, the look happy and content. But when awake, since they have a fair share of feathers, they seem to do a lot of hopping and "flying" around the box. Brooder has a hard cover on half and a hardware cloth cover on the half where the light is, so they can't escape from the box. I know I have seen "1/2 sq ft per chick" as the recommendation, but have seen few brooder photos that look like they meet this spec. Any suggestions? Nights here still drop below 65 deg., so I am not in a huge rush to put them outside. Irrational fears of a coop fire keep me from installing a heatlamp in the outdoor coop.

 

[Julie08]

Age of chicks Floor space per bird
0 to 4 weeks 1/2 square foot
4 to 8 weeks 1 square foot

 

[kburen]

I'm not sure if it's good or not...but I have the same set up waiting for my chicks (day 20)! I had my bf fix the top for me...1/2 screen and 1/2 7/8 inch holes. I'm not sure how many chicks i'll have in it either.

 

[ChickenToes]

I think you'll know when they're too crowded - it will be when they don't have a lot of room to run around, and they can't get away from each other. Chicks like to sleep all cuddled together, but tempers can run high when they're too crowded - they might be really noisy or start pecking at each other. I have my 6 week olds outside, with a lamp for heat, and the nights have been below freezing, and they're fine! They're a bit tougher than we give them credit for.