The rules (p. 9) say that, The second one. If it said "Animals that you gain during the Work phase but that you cannot or do not want to accommodate on your Home board by the end of the Work phase may be converted into Food at that time" or something similar, then it would be the first. But "immediately" means, y'know, immediately, as in, when you take the Action.
"Animals that you gain during the Work phase but that you cannot or do not want to accommodate on your Home board may be converted into Food immediately".
Does it mean that you can accumulate all the animals that you gain during the Work phase and only at the end of the phase decide whether to convert them all into Food or rearrange what you can?
Or does it mean that if you gain an animal (or animals) from a single action during the Work phase, you have the option to immediately (after gaining, or, equivalently, before the next action or the end of the Work phase) to convert them into Food, without the possibility to postpone the decision to the end of the Work phase?
Which one it is?